diff --git a/gamefixes-steam/9420.py b/gamefixes-steam/9420.py
new file mode 100644
index 0000000..f690990
--- /dev/null
+++ b/gamefixes-steam/9420.py
@@ -0,0 +1,9 @@
+"""Game fix for Supreme Commander"""
+
+from protonfixes import util
+
+
+def main() -> None:
+	"""Bad performance unless Esync and Fsync are disabled."""
+	util.disable_esync()
+	util.disable_fsync()