diff --git a/Project.toml b/Project.toml
index 5b69a55c5b..79aa0340d1 100644
--- a/Project.toml
+++ b/Project.toml
@@ -10,6 +10,7 @@ ArrayInterface = "4fba245c-0d91-5ea0-9b3e-6abc04ee57a9"
 DataStructures = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
 DiffEqBase = "2b5f629d-d688-5b77-993f-72d75c75574e"
 DocStringExtensions = "ffbed154-4ef7-542d-bbb7-c09d3a79fcae"
+EnumX = "4e289a0a-7415-4d19-859d-a7e5c4648b56"
 ExponentialUtilities = "d4d017d3-3776-5f7e-afef-a10c40355c18"
 FastBroadcast = "7034ab61-46d4-4ed7-9d0f-46aef9175898"
 FastClosures = "9aa1b823-49e4-5ca5-8b0f-3971ec8bab6a"
@@ -75,7 +76,6 @@ RecursiveArrayTools = "2.36, 3"
 Reexport = "1.0"
 SciMLBase = "2.27.1"
 SciMLOperators = "0.3"
-SciMLStructures = "1"
 SimpleNonlinearSolve = "1"
 SimpleUnPack = "1"
 SparseArrays = "1.9"
diff --git a/src/OrdinaryDiffEq.jl b/src/OrdinaryDiffEq.jl
index ae6b2001ab..4aa2e5b187 100644
--- a/src/OrdinaryDiffEq.jl
+++ b/src/OrdinaryDiffEq.jl
@@ -26,6 +26,8 @@ using LinearSolve, SimpleNonlinearSolve
 
 using LineSearches
 
+import EnumX
+
 import FillArrays: Trues
 
 # Interfaces
@@ -141,6 +143,7 @@ include("nlsolve/functional.jl")
 include("nlsolve/newton.jl")
 
 include("generic_rosenbrock.jl")
+include("composite_algs.jl")
 
 include("caches/basic_caches.jl")
 include("caches/low_order_rk_caches.jl")
@@ -234,7 +237,6 @@ include("constants.jl")
 include("solve.jl")
 include("initdt.jl")
 include("interp_func.jl")
-include("composite_algs.jl")
 
 import PrecompileTools
 
@@ -253,9 +255,14 @@ PrecompileTools.@compile_workload begin
         Tsit5(), Vern7()
     ]
 
-    stiff = [Rosenbrock23(), Rosenbrock23(autodiff = false),
-        Rodas5P(), Rodas5P(autodiff = false),
-        FBDF(), FBDF(autodiff = false)
+    stiff = [Rosenbrock23(),
+        Rodas5P(),
+        FBDF()
+    ]
+
+    default_ode = [
+        DefaultODEAlgorithm(autodiff=false),
+        DefaultODEAlgorithm()
     ]
 
     autoswitch = [
@@ -284,7 +291,11 @@ PrecompileTools.@compile_workload begin
         append!(solver_list, stiff)
     end
 
-    if Preferences.@load_preference("PrecompileAutoSwitch", true)
+    if Preferences.@load_preference("PrecompileDefault", true)
+        append!(solver_list, default_ode)
+    end
+
+    if Preferences.@load_preference("PrecompileAutoSwitch", false)
         append!(solver_list, autoswitch)
     end
 
diff --git a/src/alg_utils.jl b/src/alg_utils.jl
index d82fce2f1e..59512be35e 100644
--- a/src/alg_utils.jl
+++ b/src/alg_utils.jl
@@ -172,6 +172,7 @@ isimplicit(alg::CompositeAlgorithm) = any(isimplicit.(alg.algs))
 
 isdtchangeable(alg::Union{OrdinaryDiffEqAlgorithm, DAEAlgorithm}) = true
 isdtchangeable(alg::CompositeAlgorithm) = all(isdtchangeable.(alg.algs))
+
 function isdtchangeable(alg::Union{LawsonEuler, NorsettEuler, LieEuler, MagnusGauss4,
         CayleyEuler, ETDRK2, ETDRK3, ETDRK4, HochOst4, ETD2})
     false
@@ -205,31 +206,35 @@ qmax_default(alg::CompositeAlgorithm) = minimum(qmax_default.(alg.algs))
 qmax_default(alg::DP8) = 6
 qmax_default(alg::Union{RadauIIA3, RadauIIA5}) = 8
 
+function has_chunksize(alg::OrdinaryDiffEqAlgorithm)
+    return alg isa Union{OrdinaryDiffEqExponentialAlgorithm,
+                         OrdinaryDiffEqAdaptiveExponentialAlgorithm,
+                         OrdinaryDiffEqImplicitAlgorithm,
+                         OrdinaryDiffEqAdaptiveImplicitAlgorithm,
+                         DAEAlgorithm,
+                         CompositeAlgorithm}
+end
 function get_chunksize(alg::OrdinaryDiffEqAlgorithm)
     error("This algorithm does not have a chunk size defined.")
 end
-get_chunksize(alg::OrdinaryDiffEqAdaptiveImplicitAlgorithm{CS, AD}) where {CS, AD} = Val(CS)
-get_chunksize(alg::OrdinaryDiffEqImplicitAlgorithm{CS, AD}) where {CS, AD} = Val(CS)
-get_chunksize(alg::DAEAlgorithm{CS, AD}) where {CS, AD} = Val(CS)
-function get_chunksize(alg::Union{OrdinaryDiffEqExponentialAlgorithm{CS, AD},
-        OrdinaryDiffEqAdaptiveExponentialAlgorithm{CS, AD}}) where {
-        CS,
-        AD
-}
+function get_chunksize(alg::Union{OrdinaryDiffEqExponentialAlgorithm{CS},
+                                  OrdinaryDiffEqAdaptiveExponentialAlgorithm{CS},
+                                  OrdinaryDiffEqImplicitAlgorithm{CS},
+                                  OrdinaryDiffEqAdaptiveImplicitAlgorithm{CS},
+                                  DAEAlgorithm{CS},
+                                  CompositeAlgorithm{CS}}) where {CS}
     Val(CS)
 end
 
 function get_chunksize_int(alg::OrdinaryDiffEqAlgorithm)
     error("This algorithm does not have a chunk size defined.")
 end
-get_chunksize_int(alg::OrdinaryDiffEqAdaptiveImplicitAlgorithm{CS, AD}) where {CS, AD} = CS
-get_chunksize_int(alg::OrdinaryDiffEqImplicitAlgorithm{CS, AD}) where {CS, AD} = CS
-get_chunksize_int(alg::DAEAlgorithm{CS, AD}) where {CS, AD} = CS
-function get_chunksize_int(alg::Union{OrdinaryDiffEqExponentialAlgorithm{CS, AD},
-        OrdinaryDiffEqAdaptiveExponentialAlgorithm{CS, AD}}) where {
-        CS,
-        AD
-}
+function get_chunksize_int(alg::Union{OrdinaryDiffEqExponentialAlgorithm{CS},
+                                      OrdinaryDiffEqAdaptiveExponentialAlgorithm{CS},
+                                      OrdinaryDiffEqImplicitAlgorithm{CS},
+                                      OrdinaryDiffEqAdaptiveImplicitAlgorithm{CS},
+                                      DAEAlgorithm{CS},
+                                      CompositeAlgorithm{CS}}) where {CS}
     CS
 end
 # get_chunksize(alg::CompositeAlgorithm) = get_chunksize(alg.algs[alg.current_alg])
@@ -965,10 +970,12 @@ alg_can_repeat_jac(alg::OrdinaryDiffEqNewtonAdaptiveAlgorithm) = true
 alg_can_repeat_jac(alg::IRKC) = false
 
 function unwrap_alg(alg::SciMLBase.DEAlgorithm, is_stiff)
-    iscomp = alg isa CompositeAlgorithm
-    if !iscomp
+    if !(alg isa CompositeAlgorithm)
         return alg
     elseif alg.choice_function isa AutoSwitchCache
+        if length(alg.algs) > 2
+            return alg.algs[alg.choice_function.current]
+        end
         if is_stiff === nothing
             throwautoswitch(alg)
         end
@@ -985,18 +992,21 @@ end
 
 function unwrap_alg(integrator, is_stiff)
     alg = integrator.alg
-    iscomp = alg isa CompositeAlgorithm
-    if !iscomp
+    if !(alg isa CompositeAlgorithm)
         return alg
     elseif alg.choice_function isa AutoSwitchCache
-        if is_stiff === nothing
-            throwautoswitch(alg)
-        end
-        num = is_stiff ? 2 : 1
-        if num == 1
-            return alg.algs[1]
+        if length(alg.algs) > 2
+            alg.algs[alg.choice_function.current]
         else
-            return alg.algs[2]
+            if is_stiff === nothing
+                throwautoswitch(alg)
+            end
+            num = is_stiff ? 2 : 1
+            if num == 1
+                return alg.algs[1]
+            else
+                return alg.algs[2]
+            end
         end
     else
         return _eval_index(identity, alg.algs, integrator.cache.current)
@@ -1071,3 +1081,5 @@ is_mass_matrix_alg(alg::Union{OrdinaryDiffEqAlgorithm, DAEAlgorithm}) = false
 is_mass_matrix_alg(alg::CompositeAlgorithm) = all(is_mass_matrix_alg, alg.algs)
 is_mass_matrix_alg(alg::RosenbrockAlgorithm) = true
 is_mass_matrix_alg(alg::NewtonAlgorithm) = !isesdirk(alg)
+# hack for the default alg
+is_mass_matrix_alg(alg::CompositeAlgorithm{<:Any, <:Tuple{Tsit5, Vern7, Rosenbrock23, Rodas5P, FBDF, FBDF}}) = true
diff --git a/src/algorithms.jl b/src/algorithms.jl
index bc2a0ac0f5..da3b321e31 100644
--- a/src/algorithms.jl
+++ b/src/algorithms.jl
@@ -2969,7 +2969,7 @@ Scientific Computing, 18 (1), pp. 1-22.
   differential-algebraic problems. Computational mathematics (2nd revised ed.), Springer (1996)
 
 #### ROS2PR, ROS2S, ROS3PR, Scholz4_7
--Rang, Joachim (2014): The Prothero and Robinson example: 
+-Rang, Joachim (2014): The Prothero and Robinson example:
  Convergence studies for Runge-Kutta and Rosenbrock-Wanner methods.
  https://doi.org/10.24355/dbbs.084-201408121139-0
 
@@ -3014,16 +3014,16 @@ University of Geneva, Switzerland.
  https://doi.org/10.1016/j.cam.2015.03.010
 
 #### ROS3PRL, ROS3PRL2
--Rang, Joachim (2014): The Prothero and Robinson example: 
+-Rang, Joachim (2014): The Prothero and Robinson example:
  Convergence studies for Runge-Kutta and Rosenbrock-Wanner methods.
  https://doi.org/10.24355/dbbs.084-201408121139-0
 
 #### Rodas5P
-- Steinebach G.   Construction of Rosenbrock–Wanner method Rodas5P and numerical benchmarks within the Julia Differential Equations package. 
+- Steinebach G.   Construction of Rosenbrock–Wanner method Rodas5P and numerical benchmarks within the Julia Differential Equations package.
  In: BIT Numerical Mathematics, 63(2), 2023
 
  #### Rodas23W, Rodas3P, Rodas5Pe, Rodas5Pr
-- Steinebach G. Rosenbrock methods within OrdinaryDiffEq.jl - Overview, recent developments and applications - 
+- Steinebach G. Rosenbrock methods within OrdinaryDiffEq.jl - Overview, recent developments and applications -
  Preprint 2024
  https://github.com/hbrs-cse/RosenbrockMethods/blob/main/paper/JuliaPaper.pdf
 
@@ -3239,9 +3239,13 @@ end
 
 #########################################
 
-struct CompositeAlgorithm{T, F} <: OrdinaryDiffEqCompositeAlgorithm
+struct CompositeAlgorithm{CS, T, F} <: OrdinaryDiffEqCompositeAlgorithm
     algs::T
     choice_function::F
+    function CompositeAlgorithm(algs::T, choice_function::F) where {T,F}
+        CS = mapreduce(alg->has_chunksize(alg) ? get_chunksize_int(alg) : 0, max, algs)
+        new{CS, T, F}(algs, choice_function)
+    end
 end
 
 TruncatedStacktraces.@truncate_stacktrace CompositeAlgorithm 1
@@ -3250,6 +3254,62 @@ if isdefined(Base, :Experimental) && isdefined(Base.Experimental, :silence!)
     Base.Experimental.silence!(CompositeAlgorithm)
 end
 
+mutable struct AutoSwitchCache{nAlg, sAlg, tolType, T}
+    count::Int
+    successive_switches::Int
+    nonstiffalg::nAlg
+    stiffalg::sAlg
+    is_stiffalg::Bool
+    maxstiffstep::Int
+    maxnonstiffstep::Int
+    nonstifftol::tolType
+    stifftol::tolType
+    dtfac::T
+    stiffalgfirst::Bool
+    switch_max::Int
+    current::Int
+    function AutoSwitchCache(count::Int,
+                             successive_switches::Int,
+                             nonstiffalg::nAlg,
+                             stiffalg::sAlg,
+                             is_stiffalg::Bool,
+                             maxstiffstep::Int,
+                             maxnonstiffstep::Int,
+                             nonstifftol::tolType,
+                             stifftol::tolType,
+                             dtfac::T,
+                             stiffalgfirst::Bool,
+                             switch_max::Int,
+                             current::Int=0) where {nAlg, sAlg, tolType, T}
+        new{nAlg, sAlg, tolType, T}(count,
+                             successive_switches,
+                             nonstiffalg,
+                             stiffalg,
+                             is_stiffalg,
+                             maxstiffstep,
+                             maxnonstiffstep,
+                             nonstifftol,
+                             stifftol,
+                             dtfac,
+                             stiffalgfirst,
+                             switch_max,
+                             current)
+    end
+
+end
+
+struct AutoSwitch{nAlg, sAlg, tolType, T}
+    nonstiffalg::nAlg
+    stiffalg::sAlg
+    maxstiffstep::Int
+    maxnonstiffstep::Int
+    nonstifftol::tolType
+    stifftol::tolType
+    dtfac::T
+    stiffalgfirst::Bool
+    switch_max::Int
+end
+
 ################################################################################
 """
 MEBDF2: Multistep Method
diff --git a/src/cache_utils.jl b/src/cache_utils.jl
index bb9810562a..0297e8578f 100644
--- a/src/cache_utils.jl
+++ b/src/cache_utils.jl
@@ -8,6 +8,21 @@ function DiffEqBase.unwrap_cache(integrator::ODEIntegrator, is_stiff)
     iscomp = alg isa CompositeAlgorithm
     if !iscomp
         return cache
+    elseif cache isa DefaultCache
+        current = integrator.cache.current
+        if current == 1
+            return cache.cache1
+        elseif current == 2
+            return cache.cache2
+        elseif current == 3
+            return cache.cache3
+        elseif current == 4
+            return cache.cache4
+        elseif current == 5
+            return cache.cache5
+        elseif current == 6
+            return cache.cache6
+        end
     elseif alg.choice_function isa AutoSwitch
         num = is_stiff ? 2 : 1
         return cache.caches[num]
diff --git a/src/caches/basic_caches.jl b/src/caches/basic_caches.jl
index fa492dbe7a..7134524176 100644
--- a/src/caches/basic_caches.jl
+++ b/src/caches/basic_caches.jl
@@ -12,24 +12,26 @@ end
 
 TruncatedStacktraces.@truncate_stacktrace CompositeCache 1
 
-if isdefined(Base, :Experimental) && isdefined(Base.Experimental, :silence!)
-    Base.Experimental.silence!(CompositeCache)
+mutable struct DefaultCache{T1, T2, T3, T4, T5, T6, A, F} <: OrdinaryDiffEqCache
+    args::A
+    choice_function::F
+    current::Int
+    cache1::T1
+    cache2::T2
+    cache3::T3
+    cache4::T4
+    cache5::T5
+    cache6::T6
+    function DefaultCache{T1, T2, T3, T4, T5, T6, F}(args, choice_function, current) where {T1, T2, T3, T4, T5, T6, F}
+        new{T1, T2, T3, T4, T5, T6, typeof(args), F}(args, choice_function, current)
+    end
 end
 
-function alg_cache(alg::CompositeAlgorithm{Tuple{T1, T2}, F}, u, rate_prototype,
-        ::Type{uEltypeNoUnits}, ::Type{uBottomEltypeNoUnits},
-        ::Type{tTypeNoUnits}, uprev,
-        uprev2, f, t, dt, reltol, p, calck,
-        ::Val{V}) where {T1, T2, F, V, uEltypeNoUnits, uBottomEltypeNoUnits,
-        tTypeNoUnits}
-    caches = (
-        alg_cache(alg.algs[1], u, rate_prototype, uEltypeNoUnits,
-            uBottomEltypeNoUnits,
-            tTypeNoUnits, uprev, uprev2, f, t, dt, reltol, p, calck, Val(V)),
-        alg_cache(alg.algs[2], u, rate_prototype, uEltypeNoUnits,
-            uBottomEltypeNoUnits,
-            tTypeNoUnits, uprev, uprev2, f, t, dt, reltol, p, calck, Val(V)))
-    CompositeCache(caches, alg.choice_function, 1)
+TruncatedStacktraces.@truncate_stacktrace DefaultCache 1
+
+if isdefined(Base, :Experimental) && isdefined(Base.Experimental, :silence!)
+    Base.Experimental.silence!(CompositeCache)
+    Base.Experimental.silence!(DefaultCache)
 end
 
 function alg_cache(alg::CompositeAlgorithm, u, rate_prototype, ::Type{uEltypeNoUnits},
@@ -41,6 +43,24 @@ function alg_cache(alg::CompositeAlgorithm, u, rate_prototype, ::Type{uEltypeNoU
     CompositeCache(caches, alg.choice_function, 1)
 end
 
+function alg_cache(alg::CompositeAlgorithm{CS, Tuple{A1, A2, A3, A4, A5, A6}}, u,
+    rate_prototype, ::Type{uEltypeNoUnits}, ::Type{uBottomEltypeNoUnits}, ::Type{tTypeNoUnits},
+    uprev, uprev2, f, t, dt, reltol, p, calck,
+    ::Val{V}) where {CS, V, uEltypeNoUnits, uBottomEltypeNoUnits, tTypeNoUnits, A1, A2, A3, A4, A5, A6}
+
+    args = (u, rate_prototype, uEltypeNoUnits,
+            uBottomEltypeNoUnits, tTypeNoUnits, uprev, uprev2, f, t, dt,
+            reltol, p, calck, Val(V))
+    argT = map(typeof, args)
+    T1 = Base.promote_op(alg_cache, A1, argT...)
+    T2 = Base.promote_op(alg_cache, A2, argT...)
+    T3 = Base.promote_op(alg_cache, A3, argT...)
+    T4 = Base.promote_op(alg_cache, A4, argT...)
+    T5 = Base.promote_op(alg_cache, A5, argT...)
+    T6 = Base.promote_op(alg_cache, A6, argT...)
+    DefaultCache{T1, T2, T3, T4, T5, T6, typeof(alg.choice_function)}(args, alg.choice_function, 1)
+end
+
 # map + closure approach doesn't infer
 @generated function __alg_cache(algs::T, u, rate_prototype, ::Type{uEltypeNoUnits},
         ::Type{uBottomEltypeNoUnits}, ::Type{tTypeNoUnits}, uprev,
diff --git a/src/caches/verner_caches.jl b/src/caches/verner_caches.jl
index 08b1de0919..6de34d0559 100644
--- a/src/caches/verner_caches.jl
+++ b/src/caches/verner_caches.jl
@@ -20,6 +20,7 @@
     stage_limiter!::StageLimiter
     step_limiter!::StepLimiter
     thread::Thread
+    lazy::Bool
 end
 
 TruncatedStacktraces.@truncate_stacktrace Vern6Cache 1
@@ -44,11 +45,12 @@ function alg_cache(alg::Vern6, u, rate_prototype, ::Type{uEltypeNoUnits},
     recursivefill!(atmp, false)
     rtmp = uEltypeNoUnits === eltype(u) ? utilde : zero(rate_prototype)
     Vern6Cache(u, uprev, k1, k2, k3, k4, k5, k6, k7, k8, k9, utilde, tmp, rtmp, atmp, tab,
-        alg.stage_limiter!, alg.step_limiter!, alg.thread)
+        alg.stage_limiter!, alg.step_limiter!, alg.thread, alg.lazy)
 end
 
 struct Vern6ConstantCache{TabType} <: OrdinaryDiffEqConstantCache
     tab::TabType
+    lazy::Bool
 end
 
 function alg_cache(alg::Vern6, u, rate_prototype, ::Type{uEltypeNoUnits},
@@ -56,7 +58,7 @@ function alg_cache(alg::Vern6, u, rate_prototype, ::Type{uEltypeNoUnits},
         dt, reltol, p, calck,
         ::Val{false}) where {uEltypeNoUnits, uBottomEltypeNoUnits, tTypeNoUnits}
     tab = Vern6Tableau(constvalue(uBottomEltypeNoUnits), constvalue(tTypeNoUnits))
-    Vern6ConstantCache(tab)
+    Vern6ConstantCache(tab, alg.lazy)
 end
 
 @cache struct Vern7Cache{uType, rateType, uNoUnitsType, StageLimiter, StepLimiter,
@@ -81,6 +83,7 @@ end
     stage_limiter!::StageLimiter
     step_limiter!::StepLimiter
     thread::Thread
+    lazy::Bool
 end
 
 TruncatedStacktraces.@truncate_stacktrace Vern7Cache 1
@@ -105,16 +108,18 @@ function alg_cache(alg::Vern7, u, rate_prototype, ::Type{uEltypeNoUnits},
     recursivefill!(atmp, false)
     rtmp = uEltypeNoUnits === eltype(u) ? utilde : zero(rate_prototype)
     Vern7Cache(u, uprev, k1, k2, k3, k4, k5, k6, k7, k8, k9, k10, utilde, tmp, rtmp, atmp,
-        alg.stage_limiter!, alg.step_limiter!, alg.thread)
+        alg.stage_limiter!, alg.step_limiter!, alg.thread, alg.lazy)
 end
 
-struct Vern7ConstantCache <: OrdinaryDiffEqConstantCache end
+struct Vern7ConstantCache <: OrdinaryDiffEqConstantCache
+    lazy::Bool
+end
 
 function alg_cache(alg::Vern7, u, rate_prototype, ::Type{uEltypeNoUnits},
         ::Type{uBottomEltypeNoUnits}, ::Type{tTypeNoUnits}, uprev, uprev2, f, t,
         dt, reltol, p, calck,
         ::Val{false}) where {uEltypeNoUnits, uBottomEltypeNoUnits, tTypeNoUnits}
-    Vern7ConstantCache()
+    Vern7ConstantCache(alg.lazy)
 end
 
 @cache struct Vern8Cache{uType, rateType, uNoUnitsType, TabType, StageLimiter, StepLimiter,
@@ -143,6 +148,7 @@ end
     stage_limiter!::StageLimiter
     step_limiter!::StepLimiter
     thread::Thread
+    lazy::Bool
 end
 
 TruncatedStacktraces.@truncate_stacktrace Vern8Cache 1
@@ -171,11 +177,12 @@ function alg_cache(alg::Vern8, u, rate_prototype, ::Type{uEltypeNoUnits},
     recursivefill!(atmp, false)
     rtmp = uEltypeNoUnits === eltype(u) ? utilde : zero(rate_prototype)
     Vern8Cache(u, uprev, k1, k2, k3, k4, k5, k6, k7, k8, k9, k10, k11, k12, k13, utilde,
-        tmp, rtmp, atmp, tab, alg.stage_limiter!, alg.step_limiter!, alg.thread)
+        tmp, rtmp, atmp, tab, alg.stage_limiter!, alg.step_limiter!, alg.thread, alg.lazy)
 end
 
 struct Vern8ConstantCache{TabType} <: OrdinaryDiffEqConstantCache
     tab::TabType
+    lazy::Bool
 end
 
 function alg_cache(alg::Vern8, u, rate_prototype, ::Type{uEltypeNoUnits},
@@ -183,7 +190,7 @@ function alg_cache(alg::Vern8, u, rate_prototype, ::Type{uEltypeNoUnits},
         dt, reltol, p, calck,
         ::Val{false}) where {uEltypeNoUnits, uBottomEltypeNoUnits, tTypeNoUnits}
     tab = Vern8Tableau(constvalue(uBottomEltypeNoUnits), constvalue(tTypeNoUnits))
-    Vern8ConstantCache(tab)
+    Vern8ConstantCache(tab, alg.lazy)
 end
 
 @cache struct Vern9Cache{uType, rateType, uNoUnitsType, StageLimiter, StepLimiter,
@@ -214,6 +221,7 @@ end
     stage_limiter!::StageLimiter
     step_limiter!::StepLimiter
     thread::Thread
+    lazy::Bool
 end
 
 TruncatedStacktraces.@truncate_stacktrace Vern9Cache 1
@@ -245,14 +253,16 @@ function alg_cache(alg::Vern9, u, rate_prototype, ::Type{uEltypeNoUnits},
     rtmp = uEltypeNoUnits === eltype(u) ? utilde : zero(rate_prototype)
     Vern9Cache(u, uprev, k1, k2, k3, k4, k5, k6, k7, k8, k9, k10, k11, k12, k13, k14, k15,
         k16, utilde, tmp, rtmp, atmp, alg.stage_limiter!, alg.step_limiter!,
-        alg.thread)
+        alg.thread, alg.lazy)
 end
 
-struct Vern9ConstantCache <: OrdinaryDiffEqConstantCache end
+struct Vern9ConstantCache <: OrdinaryDiffEqConstantCache
+    lazy::Bool
+end
 
 function alg_cache(alg::Vern9, u, rate_prototype, ::Type{uEltypeNoUnits},
         ::Type{uBottomEltypeNoUnits}, ::Type{tTypeNoUnits}, uprev, uprev2, f, t,
         dt, reltol, p, calck,
         ::Val{false}) where {uEltypeNoUnits, uBottomEltypeNoUnits, tTypeNoUnits}
-    Vern9ConstantCache()
+    Vern9ConstantCache(alg.lazy)
 end
diff --git a/src/composite_algs.jl b/src/composite_algs.jl
index 9f1d4dcf6b..2c730e76b1 100644
--- a/src/composite_algs.jl
+++ b/src/composite_algs.jl
@@ -1,30 +1,8 @@
-mutable struct AutoSwitchCache{nAlg, sAlg, tolType, T}
-    count::Int
-    successive_switches::Int
-    nonstiffalg::nAlg
-    stiffalg::sAlg
-    is_stiffalg::Bool
-    maxstiffstep::Int
-    maxnonstiffstep::Int
-    nonstifftol::tolType
-    stifftol::tolType
-    dtfac::T
-    stiffalgfirst::Bool
-    switch_max::Int
-end
+### AutoSwitch
+### Designed to switch between two solvers, stiff and non-stiff
 
-struct AutoSwitch{nAlg, sAlg, tolType, T}
-    nonstiffalg::nAlg
-    stiffalg::sAlg
-    maxstiffstep::Int
-    maxnonstiffstep::Int
-    nonstifftol::tolType
-    stifftol::tolType
-    dtfac::T
-    stiffalgfirst::Bool
-    switch_max::Int
-end
-function AutoSwitch(nonstiffalg, stiffalg; maxstiffstep = 10, maxnonstiffstep = 3,
+function AutoSwitch(nonstiffalg, stiffalg;
+        maxstiffstep = 10, maxnonstiffstep = 3,
         nonstifftol = 9 // 10, stifftol = 9 // 10, dtfac = 2,
         stiffalgfirst = false,
         switch_max = 5)
@@ -41,7 +19,6 @@ function is_stiff(integrator, alg, ntol, stol, is_stiffalg)
 
     if !bool
         integrator.alg.choice_function.successive_switches += 1
-        integrator.do_error_check = false
     else
         integrator.alg.choice_function.successive_switches = 0
     end
@@ -53,7 +30,16 @@ function is_stiff(integrator, alg, ntol, stol, is_stiffalg)
 end
 
 function (AS::AutoSwitchCache)(integrator)
-    integrator.iter == 0 && return Int(AS.stiffalgfirst) + 1
+    #horrible awful hack
+    isdefault = integrator.alg isa CompositeAlgorithm{<:Any, <:Tuple{Tsit5, Vern7, Rosenbrock23, Rodas5P, FBDF, FBDF}}
+    if isdefault
+        return default_autoswitch(AS, integrator)
+    end
+    if AS.current == 0
+        AS.current = Int(AS.stiffalgfirst) + 1
+        return AS.current
+    end
+
     dt = integrator.dt
     # Successive stiffness test positives are counted by a positive integer,
     # and successive stiffness test negatives are counted by a negative integer
@@ -68,17 +54,133 @@ function (AS::AutoSwitchCache)(integrator)
         integrator.dt = dt / AS.dtfac
         AS.is_stiffalg = false
     end
-    return Int(AS.is_stiffalg) + 1
+    AS.current = Int(AS.is_stiffalg) + 1
+    return AS.current
 end
 
-function AutoAlgSwitch(nonstiffalg, stiffalg; kwargs...)
+function AutoAlgSwitch(nonstiffalg::OrdinaryDiffEqAlgorithm, stiffalg::OrdinaryDiffEqAlgorithm; kwargs...)
     AS = AutoSwitch(nonstiffalg, stiffalg; kwargs...)
     CompositeAlgorithm((nonstiffalg, stiffalg), AS)
 end
 
+function AutoAlgSwitch(nonstiffalg::Tuple, stiffalg::Tuple; kwargs...)
+    AS = AutoSwitch(nonstiffalg, stiffalg; kwargs...)
+    CompositeAlgorithm((nonstiffalg..., stiffalg...), AS)
+end
+
 AutoTsit5(alg; kwargs...) = AutoAlgSwitch(Tsit5(), alg; kwargs...)
 AutoDP5(alg; kwargs...) = AutoAlgSwitch(DP5(), alg; kwargs...)
 AutoVern6(alg; lazy = true, kwargs...) = AutoAlgSwitch(Vern6(lazy = lazy), alg; kwargs...)
 AutoVern7(alg; lazy = true, kwargs...) = AutoAlgSwitch(Vern7(lazy = lazy), alg; kwargs...)
 AutoVern8(alg; lazy = true, kwargs...) = AutoAlgSwitch(Vern8(lazy = lazy), alg; kwargs...)
 AutoVern9(alg; lazy = true, kwargs...) = AutoAlgSwitch(Vern9(lazy = lazy), alg; kwargs...)
+
+### Default ODE Solver
+
+EnumX.@enumx DefaultSolverChoice begin
+    Tsit5 = 1
+    Vern7 = 2
+    Rosenbrock23 = 3
+    Rodas5P = 4
+    FBDF = 5
+    KrylovFBDF = 6
+end
+
+const NUM_NONSTIFF = 2
+const NUM_STIFF = 4
+const LOW_TOL = 1e-6
+const MED_TOL = 1e-2
+const EXTREME_TOL = 1e-9
+const SMALLSIZE = 50
+const MEDIUMSIZE = 500
+const STABILITY_SIZES = (alg_stability_size(Tsit5()), alg_stability_size(Vern7()))
+const DEFAULTBETA2S = (beta2_default(Tsit5()), beta2_default(Vern7()), beta2_default(Rosenbrock23()), beta2_default(Rodas5P()), beta2_default(FBDF()), beta2_default(FBDF()))
+const DEFAULTBETA1S = (beta1_default(Tsit5(),DEFAULTBETA2S[1]), beta1_default(Vern7(),DEFAULTBETA2S[2]),
+                      beta1_default(Rosenbrock23(), DEFAULTBETA2S[3]), beta1_default(Rodas5P(), DEFAULTBETA2S[4]),
+                      beta1_default(FBDF(), DEFAULTBETA2S[5]), beta1_default(FBDF(), DEFAULTBETA2S[6]))
+
+callbacks_exists(integrator) = !isempty(integrator.opts.callbacks)
+current_nonstiff(current) = ifelse(current <= NUM_NONSTIFF,current,current-NUM_STIFF)
+
+function DefaultODEAlgorithm(; lazy = true, stiffalgfirst = false, kwargs...)
+    nonstiff = (Tsit5(), Vern7(lazy = lazy))
+    stiff = (Rosenbrock23(;kwargs...), Rodas5P(;kwargs...), FBDF(;kwargs...), FBDF(;linsolve = LinearSolve.KrylovJL_GMRES()))
+    AutoAlgSwitch(nonstiff, stiff; stiffalgfirst)
+end
+
+function is_stiff(integrator, alg, ntol, stol, is_stiffalg, current)
+    eigen_est, dt = integrator.eigen_est, integrator.dt
+    stiffness = abs(eigen_est * dt / STABILITY_SIZES[nonstiffchoice(integrator.opts.reltol)]) # `abs` here is just for safety
+    tol = is_stiffalg ? stol : ntol
+    os = oneunit(stiffness)
+    bool = stiffness > os * tol
+
+    if !bool
+        integrator.alg.choice_function.successive_switches += 1
+    else
+        integrator.alg.choice_function.successive_switches = 0
+    end
+
+    integrator.do_error_check = (integrator.alg.choice_function.successive_switches >
+                                 integrator.alg.choice_function.switch_max || !bool) ||
+                                is_stiffalg
+    bool
+end
+
+function nonstiffchoice(reltol)
+    x = if reltol < LOW_TOL
+        DefaultSolverChoice.Vern7
+    else
+        DefaultSolverChoice.Tsit5
+    end
+    Int(x)
+end
+
+function stiffchoice(reltol, len)
+    x = if len > MEDIUMSIZE
+        DefaultSolverChoice.KrylovFBDF
+    elseif len > SMALLSIZE
+        DefaultSolverChoice.FBDF
+    else
+        if reltol < LOW_TOL
+            DefaultSolverChoice.Rodas5P
+        else
+            DefaultSolverChoice.Rosenbrock23
+        end
+    end
+    Int(x)
+end
+
+function default_autoswitch(AS::AutoSwitchCache, integrator)
+    len = length(integrator.u)
+    reltol = integrator.opts.reltol
+
+    # Chooose the starting method
+    if AS.current == 0
+        choice = if AS.stiffalgfirst || integrator.f.mass_matrix != I
+            stiffchoice(reltol, len)
+        else
+            nonstiffchoice(reltol)
+        end
+        AS.current = choice
+        return AS.current
+    end
+
+    dt = integrator.dt
+    # Successive stiffness test positives are counted by a positive integer,
+    # and successive stiffness test negatives are counted by a negative integer
+    AS.count = is_stiff(integrator, AS.nonstiffalg, AS.nonstifftol, AS.stifftol,
+        AS.is_stiffalg, AS.current) ?
+               AS.count < 0 ? 1 : AS.count + 1 :
+               AS.count > 0 ? -1 : AS.count - 1
+    if integrator.f.mass_matrix != I || (!AS.is_stiffalg && AS.count > AS.maxstiffstep)
+        integrator.dt = dt * AS.dtfac
+        AS.is_stiffalg = true
+        AS.current = stiffchoice(reltol, len)
+    elseif (AS.is_stiffalg && AS.count < -AS.maxnonstiffstep)
+        integrator.dt = dt / AS.dtfac
+        AS.is_stiffalg = false
+        AS.current = nonstiffchoice(reltol)
+    end
+    return AS.current
+end
diff --git a/src/derivative_wrappers.jl b/src/derivative_wrappers.jl
index 236b9a82b0..13306d9bd2 100644
--- a/src/derivative_wrappers.jl
+++ b/src/derivative_wrappers.jl
@@ -284,7 +284,6 @@ function build_jac_config(alg, f::F1, uf::F2, du1, uprev, u, tmp, du2,
 
         if alg_autodiff(alg) isa AutoForwardDiff
             _chunksize = get_chunksize(alg) === Val(0) ? nothing : get_chunksize(alg) # SparseDiffEq uses different convection...
-
             T = if standardtag(alg)
                 typeof(ForwardDiff.Tag(OrdinaryDiffEqTag(), eltype(u)))
             else
diff --git a/src/perform_step/composite_perform_step.jl b/src/perform_step/composite_perform_step.jl
index 75057a3adc..2eb19e1688 100644
--- a/src/perform_step/composite_perform_step.jl
+++ b/src/perform_step/composite_perform_step.jl
@@ -1,38 +1,61 @@
-#=
-
-Maybe do generated functions to reduce dispatch times?
-
-f(x) = x
-g(x,i) = f(x[i])
-g{i}(x,::Type{Val{i}}) = f(x[i])
-@generated function gg(tup::Tuple, num)
-                  N = length(tup.parameters)
-                  :(@nif $(N+1) i->(i == num) i->(f(tup[i])) i->error("unreachable"))
-              end
-h(i) = g((1,1.0,"foo"), i)
-h2{i}(::Type{Val{i}}) = g((1,1.0,"foo"), Val{i})
-h3(i) = gg((1,1.0,"foo"), i)
-@benchmark h(1)
-mean time:        31.822 ns (0.00% GC)
-@benchmark h2(Val{1})
-mean time:        1.585 ns (0.00% GC)
-@benchmark h3(1)
-mean time:        6.423 ns (0.00% GC)
-
-@generated function foo(tup::Tuple, num)
-  N = length(tup.parameters)
-  :(@nif $(N+1) i->(i == num) i->(tup[i]) i->error("unreachable"))
+function init_ith_default_cache(cache::DefaultCache, algs, i)
+    if i == 1
+        if !isdefined(cache, :cache1)
+            cache.cache1 = alg_cache(algs[1], cache.args...)
+        end
+    elseif i == 2
+        if !isdefined(cache, :cache2)
+            cache.cache2 = alg_cache(algs[2], cache.args...)
+        end
+    elseif i == 3
+        if !isdefined(cache, :cache3)
+            cache.cache3 = alg_cache(algs[3], cache.args...)
+        end
+    elseif i == 4
+        if !isdefined(cache, :cache4)
+            cache.cache4 = alg_cache(algs[4], cache.args...)
+        end
+    elseif i == 5
+        if !isdefined(cache, :cache5)
+            cache.cache5 = alg_cache(algs[5], cache.args...)
+        end
+    elseif i == 6
+        if !isdefined(cache, :cache6)
+            cache.cache6 = alg_cache(algs[6], cache.args...)
+        end
+    end
 end
 
-@code_typed foo((1,1.0), 1)
-
-@generated function perform_step!(integrator, cache::CompositeCache, repeat_step=false)
-  N = length(cache.parameters)
-  :(@nif $(N+1) i->(i == num) i->(tup[i]) i->error("unreachable"))
+function initialize!(integrator, cache::DefaultCache)
+    cache.current = cache.choice_function(integrator)
+    algs = integrator.alg.algs
+    init_ith_default_cache(cache, algs, cache.current)
+    if cache.current == 1
+        initialize!(integrator, cache.cache1)
+    elseif cache.current == 2
+        initialize!(integrator, cache.cache2)
+        # the controller was initialized by default for algs[1]
+        reset_alg_dependent_opts!(integrator.opts.controller, algs[1], algs[2])
+    elseif cache.current == 3
+        initialize!(integrator, cache.cache3)
+        # the controller was initialized by default for algs[1]
+        reset_alg_dependent_opts!(integrator.opts.controller, algs[1], algs[3])
+    elseif cache.current == 4
+        initialize!(integrator, cache.cache4)
+        # the controller was initialized by default for algs[1]
+        reset_alg_dependent_opts!(integrator.opts.controller, algs[1], algs[4])
+    elseif cache.current == 5
+        initialize!(integrator, cache.cache5)
+        # the controller was initialized by default for algs[1]
+        reset_alg_dependent_opts!(integrator.opts.controller, algs[1], algs[5])
+    elseif cache.current == 6
+        initialize!(integrator, cache.cache6)
+        # the controller was initialized by default for algs[1]
+        reset_alg_dependent_opts!(integrator.opts.controller, algs[1], algs[6])
+    end
+    resize!(integrator.k, integrator.kshortsize)
 end
 
-=#
-
 function initialize!(integrator, cache::CompositeCache)
     cache.current = cache.choice_function(integrator)
     if cache.current == 1
@@ -69,28 +92,37 @@ the behaviour is consistent.
 In particular, prevents dt ⟶ 0 if starting with non-adaptive alg and opts.adaptive=true,
 and dt=cst if starting with adaptive alg and opts.adaptive=false.
 """
-function ensure_behaving_adaptivity!(integrator, cache::CompositeCache)
+function ensure_behaving_adaptivity!(integrator, cache::Union{DefaultCache, CompositeCache})
     if anyadaptive(integrator.alg) && !isadaptive(integrator.alg)
         integrator.opts.adaptive = isadaptive(integrator.alg.algs[cache.current])
     end
 end
 
-function perform_step!(integrator, cache::CompositeCache, repeat_step = false)
+function perform_step!(integrator, cache::DefaultCache, repeat_step = false)
+    algs = integrator.alg.algs
+    init_ith_default_cache(cache, algs, cache.current)
     if cache.current == 1
-        perform_step!(integrator, @inbounds(cache.caches[1]), repeat_step)
+        perform_step!(integrator, @inbounds(cache.cache1), repeat_step)
     elseif cache.current == 2
-        perform_step!(integrator, @inbounds(cache.caches[2]), repeat_step)
-    else
-        perform_step!(integrator, @inbounds(cache.caches[cache.current]), repeat_step)
+        perform_step!(integrator, @inbounds(cache.cache2), repeat_step)
+    elseif cache.current == 3
+        perform_step!(integrator, @inbounds(cache.cache3), repeat_step)
+    elseif cache.current == 4
+        perform_step!(integrator, @inbounds(cache.cache4), repeat_step)
+    elseif cache.current == 5
+        perform_step!(integrator, @inbounds(cache.cache5), repeat_step)
+    elseif cache.current == 6
+        perform_step!(integrator, @inbounds(cache.cache6), repeat_step)
     end
 end
 
-function perform_step!(integrator, cache::CompositeCache{Tuple{T1, T2}, F},
-        repeat_step = false) where {T1, T2, F}
+function perform_step!(integrator, cache::CompositeCache, repeat_step = false)
     if cache.current == 1
         perform_step!(integrator, @inbounds(cache.caches[1]), repeat_step)
     elseif cache.current == 2
         perform_step!(integrator, @inbounds(cache.caches[2]), repeat_step)
+    else
+        perform_step!(integrator, @inbounds(cache.caches[cache.current]), repeat_step)
     end
 end
 
@@ -121,34 +153,52 @@ function choose_algorithm!(integrator,
     end
 end
 
-function choose_algorithm!(integrator, cache::CompositeCache)
+function choose_algorithm!(integrator, cache::DefaultCache)
     new_current = cache.choice_function(integrator)
     old_current = cache.current
     @inbounds if new_current != old_current
+        algs = integrator.alg.algs
         cache.current = new_current
+        init_ith_default_cache(cache, algs, new_current)
         if new_current == 1
-            initialize!(integrator, @inbounds(cache.caches[1]))
+            initialize!(integrator, @inbounds(cache.cache1))
+            new_cache = cache.cache1
         elseif new_current == 2
-            initialize!(integrator, @inbounds(cache.caches[2]))
-        else
-            initialize!(integrator, @inbounds(cache.caches[new_current]))
+            initialize!(integrator, @inbounds(cache.cache2))
+            new_cache = cache.cache2
+        elseif new_current == 3
+            initialize!(integrator, @inbounds(cache.cache3))
+            new_cache = cache.cache3
+        elseif new_current == 4
+            initialize!(integrator, @inbounds(cache.cache4))
+            new_cache = cache.cache4
+        elseif new_current == 5
+            initialize!(integrator, @inbounds(cache.cache5))
+            new_cache = cache.cache5
+        elseif new_current == 6
+            initialize!(integrator, @inbounds(cache.cache6))
+            new_cache = cache.cache6
         end
-        if old_current == 1 && new_current == 2
-            reset_alg_dependent_opts!(integrator, integrator.alg.algs[1],
-                integrator.alg.algs[2])
-            transfer_cache!(integrator, integrator.cache.caches[1],
-                integrator.cache.caches[2])
-        elseif old_current == 2 && new_current == 1
-            reset_alg_dependent_opts!(integrator, integrator.alg.algs[2],
-                integrator.alg.algs[1])
-            transfer_cache!(integrator, integrator.cache.caches[2],
-                integrator.cache.caches[1])
-        else
-            reset_alg_dependent_opts!(integrator, integrator.alg.algs[old_current],
-                integrator.alg.algs[new_current])
-            transfer_cache!(integrator, integrator.cache.caches[old_current],
-                integrator.cache.caches[new_current])
+
+        if old_current == 1
+            old_cache = cache.cache1
+        elseif old_current == 2
+            old_cache = cache.cache2
+        elseif old_current == 3
+            old_cache = cache.cache3
+        elseif old_current == 4
+            old_cache = cache.cache4
+        elseif old_current == 5
+            old_cache = cache.cache5
+        elseif old_current == 6
+            old_cache = cache.cache6
         end
+
+        integrator.opts.controller.beta2 = beta2 = beta2_default(algs[new_current])
+        integrator.opts.controller.beta1 = beta1_default(algs[new_current], beta2)
+
+        reset_alg_dependent_opts!(integrator, algs[old_current], algs[new_current])
+        transfer_cache!(integrator, old_cache, new_cache)
     end
 end
 
@@ -170,6 +220,7 @@ function reset_alg_dependent_opts!(integrator, alg1, alg2)
         integrator.opts.qmax == qmax_default(alg2)
     end
     reset_alg_dependent_opts!(integrator.opts.controller, alg1, alg2)
+    nothing
 end
 
 # Write how to transfer the cache variables from one cache to the other
diff --git a/src/perform_step/verner_rk_perform_step.jl b/src/perform_step/verner_rk_perform_step.jl
index 0a44e217da..7c76e26719 100644
--- a/src/perform_step/verner_rk_perform_step.jl
+++ b/src/perform_step/verner_rk_perform_step.jl
@@ -2,7 +2,7 @@ function initialize!(integrator, cache::Vern6ConstantCache)
     integrator.fsalfirst = integrator.f(integrator.uprev, integrator.p, integrator.t) # Pre-start fsal
     integrator.stats.nf += 1
     alg = unwrap_alg(integrator, false)
-    alg.lazy ? (integrator.kshortsize = 9) : (integrator.kshortsize = 12)
+    cache.lazy ? (integrator.kshortsize = 9) : (integrator.kshortsize = 12)
     integrator.k = typeof(integrator.k)(undef, integrator.kshortsize)
 
     # Avoid undefined entries if k is an array of arrays
@@ -13,7 +13,7 @@ function initialize!(integrator, cache::Vern6ConstantCache)
     end
     integrator.k[integrator.kshortsize] = integrator.fsallast
 
-    if !alg.lazy
+    if !cache.lazy
         @inbounds for i in 10:12
             integrator.k[i] = zero(integrator.fsalfirst)
         end
@@ -63,7 +63,7 @@ end
     integrator.k[9] = k9
 
     alg = unwrap_alg(integrator, false)
-    if !alg.lazy && (integrator.opts.adaptive == false ||
+    if !cache.lazy && (integrator.opts.adaptive == false ||
         accept_step_controller(integrator, integrator.opts.controller))
         k = integrator.k
         @unpack c10, a1001, a1004, a1005, a1006, a1007, a1008, a1009, c11, a1101, a1104, a1105, a1106, a1107, a1108, a1109, a1110, c12, a1201, a1204, a1205, a1206, a1207, a1208, a1209, a1210, a1211 = cache.tab.extra
@@ -94,7 +94,7 @@ end
 
 function initialize!(integrator, cache::Vern6Cache)
     alg = unwrap_alg(integrator, false)
-    alg.lazy ? (integrator.kshortsize = 9) : (integrator.kshortsize = 12)
+    cache.lazy ? (integrator.kshortsize = 9) : (integrator.kshortsize = 12)
     integrator.fsalfirst = cache.k1
     integrator.fsallast = cache.k9
     @unpack k = integrator
@@ -109,7 +109,7 @@ function initialize!(integrator, cache::Vern6Cache)
     k[8] = cache.k8
     k[9] = cache.k9 # Set the pointers
 
-    if !alg.lazy
+    if !cache.lazy
         k[10] = similar(cache.k1)
         k[11] = similar(cache.k1)
         k[12] = similar(cache.k1)
@@ -182,7 +182,7 @@ end
     end
 
     alg = unwrap_alg(integrator, false)
-    if !alg.lazy && (integrator.opts.adaptive == false ||
+    if !cache.lazy && (integrator.opts.adaptive == false ||
         accept_step_controller(integrator, integrator.opts.controller))
         k = integrator.k
         @unpack c10, a1001, a1004, a1005, a1006, a1007, a1008, a1009, c11, a1101, a1104, a1105, a1106, a1107, a1108, a1109, a1110, c12, a1201, a1204, a1205, a1206, a1207, a1208, a1209, a1210, a1211 = cache.tab.extra
@@ -214,7 +214,7 @@ end
 
 function initialize!(integrator, cache::Vern7ConstantCache)
     alg = unwrap_alg(integrator, false)
-    alg.lazy ? (integrator.kshortsize = 10) : (integrator.kshortsize = 16)
+    cache.lazy ? (integrator.kshortsize = 10) : (integrator.kshortsize = 16)
     integrator.k = typeof(integrator.k)(undef, integrator.kshortsize)
 
     # Avoid undefined entries if k is an array of arrays
@@ -277,7 +277,7 @@ end
     integrator.u = u
 
     alg = unwrap_alg(integrator, false)
-    if !alg.lazy && (integrator.opts.adaptive == false ||
+    if !cache.lazy && (integrator.opts.adaptive == false ||
         accept_step_controller(integrator, integrator.opts.controller))
         k = integrator.k
         @OnDemandTableauExtract Vern7ExtraStages T T2
@@ -329,7 +329,7 @@ function initialize!(integrator, cache::Vern7Cache)
     @unpack k1, k2, k3, k4, k5, k6, k7, k8, k9, k10 = cache
     @unpack k = integrator
     alg = unwrap_alg(integrator, false)
-    alg.lazy ? (integrator.kshortsize = 10) : (integrator.kshortsize = 16)
+    cache.lazy ? (integrator.kshortsize = 10) : (integrator.kshortsize = 16)
     resize!(k, integrator.kshortsize)
     k[1] = k1
     k[2] = k2
@@ -342,7 +342,7 @@ function initialize!(integrator, cache::Vern7Cache)
     k[9] = k9
     k[10] = k10 # Setup pointers
 
-    if !alg.lazy
+    if !cache.lazy
         k[11] = similar(cache.k1)
         k[12] = similar(cache.k1)
         k[13] = similar(cache.k1)
@@ -433,7 +433,7 @@ end
         integrator.EEst = integrator.opts.internalnorm(atmp, t)
     end
     alg = unwrap_alg(integrator, false)
-    if !alg.lazy && (integrator.opts.adaptive == false ||
+    if !cache.lazy && (integrator.opts.adaptive == false ||
         accept_step_controller(integrator, integrator.opts.controller))
         k = integrator.k
         @unpack tmp = cache
@@ -489,7 +489,7 @@ end
 
 function initialize!(integrator, cache::Vern8ConstantCache)
     alg = unwrap_alg(integrator, false)
-    alg.lazy ? (integrator.kshortsize = 13) : (integrator.kshortsize = 21)
+    cache.lazy ? (integrator.kshortsize = 13) : (integrator.kshortsize = 21)
     integrator.k = typeof(integrator.k)(undef, integrator.kshortsize)
 
     # Avoid undefined entries if k is an array of arrays
@@ -575,7 +575,7 @@ end
     integrator.u = u
 
     alg = unwrap_alg(integrator, false)
-    if !alg.lazy && (integrator.opts.adaptive == false ||
+    if !cache.lazy && (integrator.opts.adaptive == false ||
         accept_step_controller(integrator, integrator.opts.controller))
         k = integrator.k
         @unpack c14, a1401, a1406, a1407, a1408, a1409, a1410, a1411, a1412, c15, a1501, a1506, a1507, a1508, a1509, a1510, a1511, a1512, a1514, c16, a1601, a1606, a1607, a1608, a1609, a1610, a1611, a1612, a1614, a1615, c17, a1701, a1706, a1707, a1708, a1709, a1710, a1711, a1712, a1714, a1715, a1716, c18, a1801, a1806, a1807, a1808, a1809, a1810, a1811, a1812, a1814, a1815, a1816, a1817, c19, a1901, a1906, a1907, a1908, a1909, a1910, a1911, a1912, a1914, a1915, a1916, a1917, c20, a2001, a2006, a2007, a2008, a2009, a2010, a2011, a2012, a2014, a2015, a2016, a2017, c21, a2101, a2106, a2107, a2108, a2109, a2110, a2111, a2112, a2114, a2115, a2116, a2117 = cache.tab.extra
@@ -642,7 +642,7 @@ function initialize!(integrator, cache::Vern8Cache)
     @unpack k1, k2, k3, k4, k5, k6, k7, k8, k9, k10, k11, k12, k13 = cache
     @unpack k = integrator
     alg = unwrap_alg(integrator, false)
-    alg.lazy ? (integrator.kshortsize = 13) : (integrator.kshortsize = 21)
+    cache.lazy ? (integrator.kshortsize = 13) : (integrator.kshortsize = 21)
     resize!(k, integrator.kshortsize)
     k[1] = k1
     k[2] = k2
@@ -658,7 +658,7 @@ function initialize!(integrator, cache::Vern8Cache)
     k[12] = k12
     k[13] = k13 # Setup pointers
 
-    if !alg.lazy
+    if !cache.lazy
         for i in 14:21
             k[i] = similar(cache.k1)
         end
@@ -764,7 +764,7 @@ end
     end
 
     alg = unwrap_alg(integrator, false)
-    if !alg.lazy && (integrator.opts.adaptive == false ||
+    if !cache.lazy && (integrator.opts.adaptive == false ||
         accept_step_controller(integrator, integrator.opts.controller))
         k = integrator.k
         @unpack c14, a1401, a1406, a1407, a1408, a1409, a1410, a1411, a1412, c15, a1501, a1506, a1507, a1508, a1509, a1510, a1511, a1512, a1514, c16, a1601, a1606, a1607, a1608, a1609, a1610, a1611, a1612, a1614, a1615, c17, a1701, a1706, a1707, a1708, a1709, a1710, a1711, a1712, a1714, a1715, a1716, c18, a1801, a1806, a1807, a1808, a1809, a1810, a1811, a1812, a1814, a1815, a1816, a1817, c19, a1901, a1906, a1907, a1908, a1909, a1910, a1911, a1912, a1914, a1915, a1916, a1917, c20, a2001, a2006, a2007, a2008, a2009, a2010, a2011, a2012, a2014, a2015, a2016, a2017, c21, a2101, a2106, a2107, a2108, a2109, a2110, a2111, a2112, a2114, a2115, a2116, a2117 = cache.tab.extra
@@ -851,7 +851,7 @@ end
 
 function initialize!(integrator, cache::Vern9ConstantCache)
     alg = unwrap_alg(integrator, false)
-    alg.lazy ? (integrator.kshortsize = 10) : (integrator.kshortsize = 20)
+    cache.lazy ? (integrator.kshortsize = 10) : (integrator.kshortsize = 20)
     integrator.k = typeof(integrator.k)(undef, integrator.kshortsize)
 
     # Avoid undefined entries if k is an array of arrays
@@ -945,7 +945,7 @@ end
     integrator.u = u
 
     alg = unwrap_alg(integrator, false)
-    if !alg.lazy && (integrator.opts.adaptive == false ||
+    if !cache.lazy && (integrator.opts.adaptive == false ||
         accept_step_controller(integrator, integrator.opts.controller))
         k = integrator.k
         @OnDemandTableauExtract Vern9ExtraStages T T2
@@ -1032,7 +1032,7 @@ function initialize!(integrator, cache::Vern9Cache)
     @unpack k1, k2, k3, k4, k5, k6, k7, k8, k9, k10, k11, k12, k13, k14, k15, k16 = cache
     @unpack k = integrator
     alg = unwrap_alg(integrator, false)
-    alg.lazy ? (integrator.kshortsize = 10) : (integrator.kshortsize = 20)
+    cache.lazy ? (integrator.kshortsize = 10) : (integrator.kshortsize = 20)
     resize!(k, integrator.kshortsize)
     # k2, k3,k4,k5,k6,k7 are not used in the code (not even in interpolations), we dont need their pointers.
     # So we mapped k[2] (from integrator) with k8 (from cache), k[3] with k9 and so on.
@@ -1047,7 +1047,7 @@ function initialize!(integrator, cache::Vern9Cache)
     k[9] = k15
     k[10] = k16 # Setup pointers
 
-    if !alg.lazy
+    if !cache.lazy
         for i in 11:20
             k[i] = similar(cache.k1)
         end
@@ -1174,7 +1174,7 @@ end
     end
 
     alg = unwrap_alg(integrator, false)
-    if !alg.lazy && (integrator.opts.adaptive == false ||
+    if !cache.lazy && (integrator.opts.adaptive == false ||
         accept_step_controller(integrator, integrator.opts.controller))
         k = integrator.k
         @unpack tmp = cache
diff --git a/src/solve.jl b/src/solve.jl
index e29136450e..dc91f4644c 100644
--- a/src/solve.jl
+++ b/src/solve.jl
@@ -146,7 +146,7 @@ function DiffEqBase.__init(
                 auto.stifftol,
                 auto.dtfac,
                 auto.stiffalgfirst,
-                auto.switch_max))
+                auto.switch_max, 0))
     else
         _alg = alg
     end
@@ -415,11 +415,9 @@ function DiffEqBase.__init(
     differential_vars = prob isa DAEProblem ? prob.differential_vars :
                         get_differential_vars(f, u)
 
-    id = InterpolationData(
-        f, timeseries, ts, ks, alg_choice, dense, cache, differential_vars, false)
+    id = InterpolationData(f, timeseries, ts, ks, alg_choice, dense, cache, differential_vars, false)
     sol = DiffEqBase.build_solution(prob, _alg, ts, timeseries,
-        dense = dense, k = ks, interp = id,
-        alg_choice = alg_choice,
+        dense = dense, k = ks, interp = id, alg_choice = alg_choice,
         calculate_error = false, stats = stats)
 
     if recompile_flag == true
@@ -534,6 +532,13 @@ function DiffEqBase.__init(
     integrator
 end
 
+function DiffEqBase.__init(prob::ODEProblem, ::Nothing, args...; kwargs...)
+    DiffEqBase.init(prob, DefaultODEAlgorithm(autodiff=false), args...; kwargs...)
+end
+function DiffEqBase.__solve(prob::ODEProblem, ::Nothing, args...; kwargs...)
+    DiffEqBase.solve(prob, DefaultODEAlgorithm(autodiff=false), args...; kwargs...)
+end
+
 function DiffEqBase.solve!(integrator::ODEIntegrator)
     @inbounds while !isempty(integrator.opts.tstops)
         while integrator.tdir * integrator.t < first(integrator.opts.tstops)
diff --git a/test/interface/default_solver_tests.jl b/test/interface/default_solver_tests.jl
new file mode 100644
index 0000000000..0a0af32148
--- /dev/null
+++ b/test/interface/default_solver_tests.jl
@@ -0,0 +1,82 @@
+using OrdinaryDiffEq, Test, LinearSolve, LinearAlgebra, SparseArrays
+
+f_2dlinear = (du, u, p, t) -> (@. du = p * u)
+
+prob_ode_2Dlinear = ODEProblem(f_2dlinear, rand(4, 2), (0.0, 1.0), 1.01)
+sol = @inferred solve(prob_ode_2Dlinear)
+
+tsitsol = solve(prob_ode_2Dlinear, Tsit5())
+# test that default isn't much worse than Tsit5 (we expect it to use Tsit5 for this).
+@test sol.stats.naccept == tsitsol.stats.naccept
+@test sol.stats.nf == tsitsol.stats.nf
+@test all(isequal(1), sol.alg_choice)
+
+sol = solve(prob_ode_2Dlinear, reltol=1e-10)
+vernsol = solve(prob_ode_2Dlinear, Vern7(), reltol=1e-10)
+# test that default isn't much worse than Tsit5 (we expect it to use Tsit5 for this).
+@test sol.stats.naccept == vernsol.stats.naccept
+@test sol.stats.nf == vernsol.stats.nf
+@test all(isequal(2), sol.alg_choice)
+
+prob_ode_linear_fast = ODEProblem(ODEFunction(f_2dlinear, mass_matrix=2*I(2)), rand(2), (0.0, 1.0), 1.01)
+sol = solve(prob_ode_linear_fast)
+@test all(isequal(3), sol.alg_choice)
+# for some reason the timestepping here is different from regular Rosenbrock23 (including the initial timestep)
+
+function rober(u, p, t)
+    y₁, y₂, y₃ = u
+    k₁, k₂, k₃ = p
+    [-k₁ * y₁ + k₃ * y₂ * y₃,
+      k₁ * y₁ - k₃ * y₂ * y₃ - k₂ * y₂^2,
+      k₂ * y₂^2]
+end
+prob_rober = ODEProblem(rober, [1.0,0.0,0.0],(0.0,1e3),(0.04,3e7,1e4))
+sol = solve(prob_rober)
+rosensol = solve(prob_rober, AutoTsit5(Rosenbrock23(autodiff=false)))
+# test that default has the same performance as AutoTsit5(Rosenbrock23()) (which we expect it to use for this).
+@test sol.stats.naccept == rosensol.stats.naccept
+@test sol.stats.nf == rosensol.stats.nf
+@test unique(sol.alg_choice) == [1,3]
+@test sol.alg_choice[1] == 1
+@test sol.alg_choice[end] == 3
+
+sol = solve(prob_rober, reltol=1e-7, abstol=1e-7)
+rosensol = solve(prob_rober, AutoVern7(Rodas5P(autodiff=false)), reltol=1e-7, abstol=1e-7)
+# test that default has the same performance as AutoTsit5(Rosenbrock23()) (which we expect it to use for this).
+@test sol.stats.naccept == rosensol.stats.naccept
+@test sol.stats.nf == rosensol.stats.nf
+@test unique(sol.alg_choice) == [2,4]
+@test sol.alg_choice[1] == 2
+@test sol.alg_choice[end] == 4
+
+function exrober(du, u, p, t)
+    y₁, y₂, y₃ = u
+    k₁, k₂, k₃ = p
+    du .= vcat([-k₁ * y₁ + k₃ * y₂ * y₃,
+      k₁ * y₁ - k₃ * y₂ * y₃ - k₂ * y₂^2,
+      k₂ * y₂^2, ], u[4:end])
+end
+
+for n in (100, ) # 600 should be added but currently is broken for unknown reasons
+    stiffalg = n < 50 ? 4 : n < 500 ? 5 : 6
+    linsolve = n < 500 ? nothing : KrylovJL_GMRES()
+    jac_prototype = sparse(I(n+3))
+    jac_prototype[1:3, 1:3] .= 1.0
+
+    prob_ex_rober = ODEProblem(ODEFunction(exrober; jac_prototype), vcat([1.0,0.0,0.0], ones(n)),(0.0,100.0),(0.04,3e7,1e4))
+    sol = solve(prob_ex_rober)
+    fsol = solve(prob_ex_rober, AutoTsit5(FBDF(;autodiff=false, linsolve)))
+    # test that default has the same performance as AutoTsit5(Rosenbrock23()) (which we expect it to use for this).
+    @test sol.stats.naccept == fsol.stats.naccept
+    @test sol.stats.nf == fsol.stats.nf
+    @test unique(sol.alg_choice) == [1,stiffalg]
+end
+
+function swaplinear(u, p, t)
+    [u[2], u[1]].*p
+end
+swaplinearf = ODEFunction(swaplinear, mass_matrix=ones(2,2)-I(2))
+prob_swaplinear = ODEProblem(swaplinearf, rand(2), (0., 1.), 1.01)
+sol = solve(prob_swaplinear, reltol=1e-7) # reltol must be set to avoid running into a bug with Rosenbrock23
+@test all(isequal(4), sol.alg_choice)
+# for some reason the timestepping here is different from regular Rodas5P (including the initial timestep)
diff --git a/test/runtests.jl b/test/runtests.jl
index 6cdf509647..a15d6044dc 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -52,6 +52,7 @@ end
         @time @safetestset "Controller Tests" include("interface/controllers.jl")
         @time @safetestset "Inplace Interpolation Tests" include("interface/inplace_interpolation.jl")
         @time @safetestset "Algebraic Interpolation Tests" include("interface/algebraic_interpolation.jl")
+        @time @safetestset "Default Solver Tests" include("interface/default_solver_tests.jl")
     end
 
     if !is_APPVEYOR && (GROUP == "All" || GROUP == "InterfaceII" || GROUP == "Interface")