I don't really understand what u r trying to say and why downclocking heats up component? What do u mean by voltage, supllied and not being used up? and how downclocking doesn't use up all the power?

Actually the effect of downclock and undervolt is much less serious compared to overclock and overvolt. Well, I'm not sure how exactly undervolt can kill CPU, but undervolt inappropriately WILL make the CPU unstable.

However, I don't think underclocking CPU without decreasing Vcore can destroy the CPU in anyway. The theory is simple. A merc can run at 180kph and 60kph well, and running at 60kph actually can preserve the engine more than running at 180kph.

Another fact to backup my point is that, both AMD and Intel use undervolt and downclock to reduce the idle core. They are striving even harder to develop better mechanism to implement undervolt + downclock more aggressively in future. If this is going to kill the CPU or shorten the lifespan, why AMD and Intel is heading towards this direction?

Merom can jimat banyak, because default multi can go as high as 15x. With low bus speed, 6x can actually brings the CPU below 1000MHz. Well, Core2 Duo initial design is for laptop usage, high FSB is not the target. So i guess 6x is pretty sufficient for initial usage.