diff --git a/bin/wsim b/bin/wsim
index 6df11e6b5..ca44e22a6 100755
--- a/bin/wsim
+++ b/bin/wsim
@@ -91,6 +91,7 @@ prefix = ""
 if (args.lockstep or args.lockstepverbose or args.fcov or args.fcovimp):
     if (args.sim == "questa" or args.sim == "vcs"):
         prefix = "IMPERAS_TOOLS=" + WALLY + "/config/"+args.config+"/imperas.ic"
+# Force Questa to use 64-bit mode, sometimes it defaults to 32-bit even on 64-bit machines
 if (args.sim == "questa"):
     prefix = "MTI_VCO_MODE=64 " + prefix