I run my GF3 ti 200 at 210/470. However, it runs stable at 233/520. I don't run it at that speed, though, because it builds up heat, and I don't need that much performance right now. When it gets slow, I'll bump it up. I've actually gotten the mem up to 530 without a problem, but I didnt' test it extensively at that speed, and 535 gave me big bars o' color and a lockup.