diff --git a/Getting-optimal-vsync-performance.md b/Getting-optimal-vsync-performance.md
index 53a97b0..fe0fc86 100644
--- a/Getting-optimal-vsync-performance.md
+++ b/Getting-optimal-vsync-performance.md
@@ -26,6 +26,8 @@ To enable it, set `video_hard_sync = true` in config. To ensure that this sync m
 
 Do note that this sync method can greatly reduce performance, and can turn smooth 60 fps into crawling 30 fps if there was not enough headroom in the performance.
 
+If you use [[KMS mode]], using `video_hard_sync` won't help as it already does something like this.
+
 ## Threaded video fallback
 If your video driver has very bad performance, it is possible to run it on a thread to avoid almost all video driver overhead. Set `video_threaded = true` in config. Butter smooth VSync behavior in this case is impossible however, and latency might increase slighly. Use only if you cannot obtain full speed otherwise.