The power Saving Guide

For a guide like this one i would like to see some undercloking results(not FPS or MB/s but power differences) and what difference does it make to underclock and undervolt a CPU. for a power saving computer we dont need cutting edge performance and if we undervolt a E6600 or a X2 4400 it will probably reduce our wattage by a little without stopping us from web surfing and some light gaming or watching a DVD... and if it's better to buy a slower stock clock CPU EG. E4300/4400 or an 6420/6600 and underclock it. we could probably go for a aftermarket cooler and stop the noise also... maybe in Part 3 we can see that in action