Update: Looks like Apple was telling the truth! Just a short time after I posted this, it was reported by people with the issue that the 10.6.7 update fixes everything. Good work, Apple.
It appears that the new MacBook Pros (introduced in February) aren’t quite fully baked. Or rather, they’re a bit overdone: there seems to be a pervasive overheating issue related to the new discrete Radeon GPUs.
The crash occurring during times of high heat and CPU load, when the GPU is switched on to handle graphics that are just too much for the CPU alone. The computers are freezing up quite completely, and a hard reboot seems the only universal cure. One person suffering from this issue even reproduced it in every susceptible model on the floor at an Apple store, baffling (and hopefully disillusioning) one of the “geniuses.”
Apple has noted the issue and claims it is a software problem, fixable via updated drivers. Of course, they say that about everything, and of course if you severely limit use of the GPU and blast the fan at all times, technically that is a software solution. But iFixit pointed out in their teardown that the thermal situation of the processing units isn’t exactly the neatest (above), and suggested this sloppy slathering might cause issues down the road. It’s too early to tell whether that’s the case, but it’ll sure be embarrassing if it is.