For me, on PS3, it tends to freeze or become unplayably laggy an average of about 30 minutes after starting it up, although that can change if I'm playing through any of the DLC. Lag and freezing tends to be significantly more frequent in the outdoor areas of the Old World Blues and Lonesome Road DLCs (usually about 10 minutes of being outdoors does the trick), while Honest Hearts and Dead Money are actually downright stable. Certain areas of the vanilla game are also really bad offenders when it comes to performance, namely the Hidden Valley bunker, the Strip, and the Strip casinos. So it's pretty much an unplayable mess for me, which is a real shame since it's also one of the best games ever made.