I don't know why there are so many complaints regarding the game on PC

I just bought it and I am playing on ultra with only a 4850 ati with 512mb video card.
My cpu is quite good tho, so maybe that has something to do with it i7 2600k.

I can even record with fraps at high settings with no fps drop, on ultra there is drop tho

Make sure you have the latest ati drivers

Well, thats nice for you. Unfortunately most are not this lucky.

I got an ATI 6870 1GB with an AMD 940 and 4 GB RAM. Still the FPS is just about 30 max in towns. And all my drivers are updated. Hence I'm able to run BF3 with about 60 FPS.

Same GPU as you, but a AMD Phenom II x3 OC'ed to 3.6GHz. I get 60fps indoors, but 20-30 elsewhere. Ridiculous.

Give this a try, manually change the AA and Antistropic filter from application managed to 8x and 16x from the Ati Catalyst center

I have a GTX 580 + the latest drivers and the shadow bug is killing my game. Its not use error. The game is optomized for lowend and old hardware. They apparently either didnt test it with new hardware, or they hoped that having massive computing power would overcome lazy coding and QC.

I don't even use AA. And setting them in CC doesn't help.