Apple put the word out that it will fix Macbook Pros with a faulty NVIDIA chip for free, although customers should expect the operation to take a few days (our guess). An investigation by Apple found that some GeForce 8600 GT GPU were defective. Scrambled video playback is the symptom that Apple was looking into.
From Apple’s support site:
At that same time, NVIDIA assured Apple that Mac computers with these graphics processors were not affected. However, after an Apple-led investigation, Apple has determined that some MacBook Pro computers with the NVIDIA GeForce 8600M GT graphics processor may be affected. (link and more info)
15″ and 17″ Macbook Pro might be affected. If you missed the NVIDIA defective chips episode: NVIDIA has had issues during the manufacturing process of the chip. A combination of materials and temperature can reveal a chip defect that would otherwise not appear. The “logic” (or design) of the chip is not at fault, only the manufacturing – but this still requires a replacement and I suspect that NVIDIA is the one really paying for it.