Looks like something running in the background, like a 1/4" square...

Win7 64, GTX 480 SLi

I'm getting this too. It's like a desktop icon is popping through the game overlay or something. Then started thinking it's a one frame glitch when lights are loaded in the distance. it's weird.

Win7 64, GTX 460

I'm getting this as well and so far it's my only issue with the game. I am also running a GTX460 on Win7 64.

I believe it is a known issue with Nvidia cards. This might help:

http://www.gamesas.com/index.php?/topic/1123359-anti-aliasing-nvidia/

Having the exact same issue, actually alt-tabbed out of the game annoyed thinking either mail or an IM client was messing with the game.

Specs are :

i7 920
2x 460 GTX in SLI
12 gigs ram
256GB SSD

I also had a few random crashes where the dreaded "Nvidia driver has stopped responding" error would come up once I got back to the desktop.

Hoping OB fixes this quickly, you can see the potential in the game behind the bugs.

Thanks, I guess I missed that post. I'll give it a try and see how it goes, but either way its only a minor annoyance and from reading here I guess I should be glad that's the only problem I am having.