Normal behaviour or not, it's a. fraudulent advertisement and b. palin stupid on behalf of manufacturer IMO.
a. If advertises claim that the laptop does something, it should do it, right? So, if doing thing causes the laptop not being able to do the thing, the laptop can be considered incapable of actually doing the thing in the first place. The car metaphor was quite adequate.
If I plugged a dual turbo on a Nissan Sunny from 1985 and sold it saying that it accelerates to 100 km/h in 8 seconds (not gonna happen but anyway...) and didn't mention that if you accelerate to that 100 km/h three times in a row, the modded engine components produce enough heat that it wont accelerate that fast anymore (or worse, suffers an engine failure), I'd be considered a car dealer from the worst end, I think.
b. It's plain stupid because the manufacturer could achieve the same overall performance with equipment that is not as fast but doesn't generate that much heat either, so it could even be more efficient in long run. As for fast responsiveness in normal programming, I'd agree that a video card of that quality is kinda overshot... Also, if the computer is not full of spyware, a weaker processor would do its work just as well in normal processing, like using Word, Excel, Mediaplayer (

) and other traditional of Windows applications. That processor really comes in useful IN extensive use, but since extensive use causes too much heat, I think it could well be replaced with a weaker processor that could longer and better maintain its original capacity because not generating as much heat.
I suppose a laptop would benefit more of additional memory in using basic applications and, for example, Photoshop and stuff. So it would be as responsive with, say, a little slower video card and a little slower processor, but having 2 GB memory. It would be cheaper to manufacture with lower prices on GPU and CPU, and it would work better along the specs.
One solution would be to connect an additional display, keyboard, mouse and speakers, throw the machine itself into freezer and play along.

A real redneck-1337 solution for cooling problems...