Here we go again. The new 17 inch MacBook Pros seem to be having some video issues. The crux of the problem is that the when 9600M not embedded video card is being used, the thing gets a little hot. So hot, in fact, that weird things start happening to the video (see picture). A work around found on Apple‘s Forums is artificially kicking the fan in at a lower temperature with SMC fan tools. These need to be reconfigured after every restart – but obviously until Apple kicks in some update, this is the best option you have. NVIDIA and Apple are so far quiet but look for a Unibody firmware update that kicks in the fans a little earlier in the overheating process. Soon, hopefully!
There were similar issues with the MacBook Airs last year.