Comment 20 for bug 1049214

Yes, I've seen the same issue with nvidia for a long time (before 310). It is horribly slow if you have vsync enabled in the driver and compiz. I suspect the reason is this bug. Nvidia appears to push lots of graphics commands through the X event queue, which no other driver does. So nvidia's hyper-sensitive to X event traffic and can slow down easily. That's the theory.

Alistair: Please note that glxgears IS doing 4000 FPS when it says so. Just like any software benchmark it's telling you the number of frames it has rendered per second. In a compositing environment this has absolutely nothing to do with the physical frame rate however. You should use the compiz Benchmark plugin to get the real physical frame rate.