Ever since the game launched I've been having issues on my PC with the mouse lagging after an hour of play, or so. I can usually tell when this happens as my weapons move very choppy-like. Unplugging my mouse and plugging it back in works for a while, but it comes back quite fast after the initial lagging. I've turned down the look sensitivity in the game and turned my mouse dpi up, but I've not played with theses settings long enough to see if it will help.

Wondering if anyone else has had this issue. I don't get this in other games and my PC is quite the beast with no slowdown on Ultra. I know that's not the issue.

I've had this problem too after moving from one map to another (or outside to inside or vice-versa). I haven't experienced it yet with Patch 1.3, but not played the updated version long enough to see whether the problem has been cured. It looks and feels like a memory (garbage collecting) problem - perhaps due to allocated RAM or video RAM not being cleaned up properly.

That's precisely the issue I'm having. Like you said it usually begins after travel or entering/exiting a location. I played the patched version and this issue still persists.