Ill give that a try, I know when you under volt you have to declock but wasn't sure if you could get good performance just by under clocking, id rather just under clock than under volt. more complicated process. and i don't know wtf i put my voltmeter its been a long time since I've needed it.
Yes underclocking is easier since it just involves changing the speed. The resulting decrease in power is usually linear - if you go down 30% in speed you see about 30% decrease in power.
By undervolting the chips are usually not able to run as fast so they would require an underclock as well and require a little fiddling to find a stable maximum speed but a 30% reduction in power would be significantly less - closer to 50-60% decrease in power due to the fact power is the square of the amperage.