diff --git a/passes/opt/muxpack.cc b/passes/opt/muxpack.cc
index dc00440c074..4e9291bd5af 100644
--- a/passes/opt/muxpack.cc
+++ b/passes/opt/muxpack.cc
@@ -371,7 +371,7 @@ struct MuxpackPass : public Pass {
 		extra_args(args, argidx, design);
 
 		if (splitfanout)
-			Pass::call(design, "splitfanout -limit 512 t:$mux t:$pmux");
+			Pass::call(design, "splitfanout -limit 256 t:$mux t:$pmux");
 
 		int mux_count = 0;
 		int pmux_count = 0;