PC Stats has posted an article about underclocking the PC

PCstats knows overclocking. You know overclocking. Everybody knows overclocking. The PC runs faster and hotter, provides more performance, and yadda yadda yadda. Overclocking has become so routine in the hardware world that every processor, motherboard, memory module and videocard needs to be overclocked as part of its review. We never know if the people actually buying the hardware care about its overclocking potential, but as computer journalists and enthusiasts, we know we have to test it out. This got us thinking though; what about under-clocking? Most modern processors and motherboards can just as easily run under a rated speed as it can run over... but is there a point to this? Well possibly.

The Underclocking Experiment