Multi-window vertical sync


How do you deal with multi-window vertical sync? I have been experiencing issues on OSX. Similar problems came up a couple of times in the past, but I’m not sure if it has ever been solved.

  • if vertical sync is enabled for both windows (on separate displays) the frame rate drops from 60 to 30 fps
  • if vertical sync is enabled in one of the windows draw function, and disabled in the other’s, frame rate still drops
  • if vertical sync is disabled for both windows, frame rate is 60 fps, but tearing is visible

The most annoying thing is that frame rate drop does not always happen, only sometimes. Probably when the two vertical sync waiting collides somehow. But I have no idea what is happening when only one window has vertical sync enabled.

Any help would be greatly appreciated.

When I open a second window, FPS drops in half

Could you disable the frame rate limiter and tell me what the effect is?


Thanks Paul for the suggestion. It seems to be related to the frame rate limiter, indeed. Frame rate drops occasionally when vertical sync is enabled for both or either of the windows and the frame rate limiter is enabled. If the frame rate limiter is disabled the fps is back on 60fps again. So I’m going to try disabling the frame rate limiter from now on, and see if it causes any issues. Thanks again!