IMO a more likely answer: 32ms / 2 = 16ms, the typical frame time for a monitor running at 60 Hz. Also the post noted disabling QuartzExtreme (GPU accelerated

IMO a more likely answer: 32ms / 2 = 16ms, the typical frame time for a monitor running at 60 Hz. Also the post noted disabling QuartzExtreme (GPU accelerated rendering) fixed the issue. I suppose the mouse cursor is drawn with GPU acceleration. Then, to optimise rendering, the window system uses double buffering (a common technique) - however, double-buffering has the well-known side-effect of introducing a one frame delay. So it would take 16ms to see your mouse cursor update, but with double buffering it takes 32ms. I think Windows uses a special graphics card feature (an "overlay" IIRC) to update the mouse cursor independently of the double buffered window system. I noticed moving windows became ever so slightly more laggy going from XP to Vista - probably because the window system became GPU accelerated.