In my case, I'm also running in windowed mode, except I don't have Windows Media Player running (nor do I know where it is to run it with). Normally, with fps_max at 200 and with nothing in the view at all, I should expect to come very close to 200 fps, but I only manage 63. I have other experiments I wanted to do, but with this behavior, the results are very unreliable due to a very large margin of error (about 30%, likely more).