Nearly unplayable on my PC and i can run BF3 on Medium at 1080p, my hardwares ancient though so I need to upgrade. Although, I'm on the fence since the PS4 will be able to run it exactly like the PC besides for no mouse/keyboard and the graphics are slight worse. But the gap from PC to PS4 is not as bad as PC to PS3, so it's tempting to buy it on PS4 instead of rebuilding my PC (4gb DDR2 LOL, Quad Phenom 3ghz, 560ti).
The game runs very smooth on PS3, i tried it on PC and it runs like poop. Then again i have old hardware and a lot of others said the same. The graphics, animations, UI, almost everything is better....Not just a rehash like COD, BF4 is an upgrade in nearly every way.