On launch, stable 30+ FPS at first in open areas AND cities. But as it progresses it gets more laggy and soon after 15-20mins it grinds to a halt, requiring a visit to the task manager to force close the game.
Computer Specs:
Intel Core2 Quad Q8200 2.33Ghz
4096MB RAM
Geforce GTX 550 Ti
600GB HD (20.2GB free)