Commonly, a GPU will produce screen artifacts before dying completely. A game exhibiting flashes, specs or bright colored anomalies is either the result of a driver related issue or (more likely) a defective GPU. Usually the problem worsens as the temp rises, but not always.
And about the GPU temps. Most graphic chips run hot, and are *supposed* to operate fine at such temps (80-100c). This isn't a guess, it's published information. A MBP becoming burning hot under load is not necessarily a symptom of a defective product. The problem is that nVidia's chips are not living up to their specs.
Great.. This is what's happening with mine.I think i need to give apple a call.