For those who found their 8600GT with fault, and had it replaced, did the problem come back? Are there people out there who have this combination and do gaming who have not experienced this problem? If so, what model did you have? I'm not a huge fan of the new uMBPs and want an older 15" but I'm worried about the video chip problem. However if it can be fixed either proactively or reactively, I"ll be happy with that. Thanks.