Intel SpeedStep config

Ok, I have windows XP pro corp on my HP ZE4530US notebook. I want to get the cpu (2.4 mobile celly) I want to get it to throttle down to maybe 700 or 800 when on battery. Can anyone tell me how to do this..Ive read that speedstep is included in xp, but if thats true, the configurablilty sucks you know what! Ive also downloaded SpeedSwitch XP, but the Demote/PromotePercent things are beyond me. Can anyone tell me what to do?! The lappy wont run more that 1 hr on battery no matter what i do. Ive put new thermal grease on that helped quite a bit but i get sucky battery life (about 1 hr with backlight turned all the way down, no hdd or cd rom running)!!!! Thanks for the awesome help!