Got the same problem with the crashing, GTX 560 Ti here. Well the screen locks up. So basically what happens is that if I play the game at 1920x1200 resolution with textures high, shadows and effects at ultra, everything else at high. Game will crash in multiplayer exactly in 10 minutes! If I drop down textures to medium, shadows and effects from ultra to high. The crashing does not happen.
But the problem with textures being medium, is that the game looks a bit ugly. I am not used to playing my games with medium settings. Considering that Battlefield 3 is the only game that crashes and locks up when trying to increase the graphics details to high. I tried every solution but to no avail.
The game just gives up on you, no matter what.
The funny thing is though, single player does not cause me this problem. Only in Multiplayer it happens.
In Battlefield Bad Company 2, Crysis, etc all run perfectly smooth with no crashes/lock-ups.
Also my BF3 is running very smoothly with 50-60 frames per second. So the problem lies somewhere else..