Xtremedays
Android Expert
With apps like Setcpu, you can set up profiles to underclock the cpu when the screen is off and overclock it when it is on, or during charging, above certain battery percentage, etc.
Check this link for a guide to Setcpu: http://androidforums.com/evo-4g-all-things-root/210253-setcpu-guide.html
Check this link for a guide to Setcpu: http://androidforums.com/evo-4g-all-things-root/210253-setcpu-guide.html