I've just installed DX:HR via Steam, and I've noticed there's really bad mouse/keyboard lag in the game. Framerate seems fine for the most part, but when I move the mouse, there's about a quarter or half-second delay before my aim moves. It's making the game almost unplayable -- I just had to struggle for a second or two to open a vent because I kept overcorrecting.
Does anybody know why this happens? How can I fix it?
I'm using a wireless keyboard and mouse, but they don't have any noticeable lag when typing or moving the cursor. Even the cursor on the in-game menus doesn't have lag.