I have a monitor with a 5ms response time, 60hz refresh rate, a deathadder (3500DPI version) with the latest drivers & firmware installed, I have the "flip qeue size" setting set to 0, and most of my games run at 40+FPS--yet I still get an insane amount of input lag in a lot of these games. Oh, and I never use Vsync--and the Windows 7 mouse acceleration is disabled using this fix. An example is that I run the Witcher 2 @ 40FPS average. If I disable SSAO, my FPS doesn't increase all that much, but I get a significant reduction in input lag. I've also noticed that there are various settings in various games where even though they don't affect my FPS much, the differences in the mouse lag is huge. I've also noticed that Desktop Window Manager Session Manager (DWM) in Vista/7 induces a great deal of input lag when enabled--but a friend who owns an NVIDIA card doesn't get this issue with DWM (nor does he get it with TW2 or any other instance where it occurs for me). Perhaps this is an ATI driver problem? I'm currently running the June 27th build of the Catalyst 11.7 drivers.