Coming to a laptop
near you soon, well vaguely soon-ish, from AMD/ATI branded PowerXPress.
Even more interesting is the platform's support for a feature called PowerXPress. The idea is that all Puma notebooks will have integrated graphics, but they can also have optional discrete graphics for better gaming performance. AMD is confident that its integrated graphics will be lower power than any discrete graphics solution, so when you're running on battery power the external graphics core would be disabled and your display would run off of the integrated GPU. On AC power, in the max performance mode, the internal graphics gets disabled and the external GPU is operational.
According to AMD, this switchover happens seamlessly; there's no reboot required and there should be hardly any interruption in use. We have yet to see it in action and are understandably skeptical of how smooth the transition between GPUs would be, but AMD claims that it works and very well at that. AMD also mentioned that this functionality could be overridden by a control panel if need be.
Not all GPUs are so power hungry, the now dated Radeon 9600 series used <20w under load for the lower models and will drive Vista's Aeroglass and older games just fine. I'm using an X1950pro that I believe is ~50w under load and not exactly a slow card, but the above technology does look promising.