My specs are as follows:
Intel Core i7-2920XM
AMD Radeon 6990M
I'm running the game at the 'medium' preset, with a configuration file tweak to disable SSAO. I get between 40 and 60 fps most of the time, and as long as I don't die the game plays perfectly fine, and I was able to play multiplayer for a good hour with no problems.
Not sure if my saves are corrupted or something, but I've been through numerous checkpoints and it still crashes when I try and reload one, but not the first time I launch the game.