Mouse Lag

[Windmill]

Hey, I recently bought Amnesia and am experiencing some bad mouse lag. It's really odd, I noticed the mouse cursor in the main menu not having a smooth, sliding animation, if you will, but I thought it was just a small developmental oversight. Note, at this time, the flame in the main menu is flickering smoothly. So, I start a game, and the opening cutscene of the player fading in and out of stream of consciousness occurs smoothly, but when I noticed that you can look around during these scenes, I found the movement of my camera to be very rough and lack fluidity that you would normally find in just browsing your desktop.

Specs:
Processor: i7 965 OC'd to 4.0ghz
GPU (x2): SLi GTX 280
RAM: 6GB
Mouse: Logitech G5

Any help would be appreciated, because this mouse lag makes the game unplayable.

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Okay, Update:
I just turned everything to the lowest setting and the mouse lag seems to have gone away.. but, I really dont understand what can be taxing my system. Sampling?