Like idle time ... I expect that most people will stress their CPU's much more heavily than their GPU's. Productivity software, music playback, background threads checking email, instant messages, etc. all require more CPU than GPU, whereas games, photo and video editing are probably the only mainstream apps with much of a GPU need. Take into consideration multi-tasking wherein you've got active apps that aren't displaying anything, and it becomes even clearer that the CPU is pulling a lot more weight than the GPU. I don't dispute that in a head-to-head folding race the GPU may still come out ahead, but it's got a major jump-start in the idle-time department.