I'm not totally sure about GPUs either, but with CPUs:But I think (and I can be wrong) that even with an efficient power management, a more powerful dedicated GPU still spread much more heat than a less capable one, even when not in intensive use.
A quad-core 2.53 GHz is 45 W.
A dual-core 2.53 GHz is 25 W or 35 W.
A quad-core 2.53 GHz with two cores active and two cores idle is (45 W)/2 = 22.5 W, less than either dual-core.
That's my thoughts. A more powerful *PU doesn't need as much resources to do a defined task as a less powerful one. But then again, the more powerful *PU is hotter when maxed out, so the advantages seem to even out.
That might be because the MBP is a very thin laptop.When watching DVDs, I put the MBP on my belly while laying on my bed, sometimes it gets inconveniently hot, comparing to any other laptop I had before.![]()