diff --git a/src/main.c b/src/main.c
index f1b65b6..a53e45f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -969,7 +969,8 @@ HRESULT WINAPI DirectDrawCreate(GUID FAR* lpGUID, LPDIRECTDRAW FAR* lplpDD, IUnk
             "maintas=false\n"
             "; use letter- or windowboxing to make a best fit\n"
             "boxing=false\n"
-            "; real rendering rate, -1 = screen rate, 0 = unlimited, n = cap\n"
+            "; real rendering rate, -1 = screen rate, 0 = unlimited (GDI), 0 = 125 (OpenGL), n = cap\n"
+            "; Note: maxfps+GDI renderer can be used to slow the game speed down, maxfps+OpenGL will not slow it down\n"
             "maxfps=0\n"
             "; vertical synchronization, enable if you get tearing (OpenGL only)\n"
             "vsync=false\n"
diff --git a/src/render.c b/src/render.c
index 56670e8..a9c9d66 100644
--- a/src/render.c
+++ b/src/render.c
@@ -77,6 +77,9 @@ DWORD WINAPI render_main(void)
     if (ddraw->render.maxfps < 0)
         ddraw->render.maxfps = ddraw->mode.dmDisplayFrequency;
 
+    if (ddraw->render.maxfps == 0)
+        ddraw->render.maxfps = 125;
+
     if (ddraw->render.maxfps > 0)
         frame_len = 1000.0f / ddraw->render.maxfps;