This morning, I listened to a couple Channel9 podcasts with Pat Helland where he discussed the Many-Core movement.
There has been a lot of talk about parallelism and many-core computing, but Pat helped to put this in context. Pat explained the issues around cpu power consumption, the slowing rate of frequency increases. The fact that chips used to draw around 8 watts but now consume 150 watts helps explain why energy consumption is a hot topic in the data-center world.
Based on this historical context, it makes a lot of sense why we'd move toward a many-core architecture. Instead of one big, hot cpu, we can run multiple cores. If we have many cores available, then the cores don't need to be as powerful. This can drastically reduce the power consumption and therefor the heat output. If I understand the gist of the numbers correctly, we could run 4 less powerful cores using a total of 75 watts versus a single powerful cpu at 150 watts.
I also enjoyed his "Memories, Guesses and Apologies" talk. I'm not going to try and explain it here. Just give a listen.