So i just FINALLY got my i5 750 stable at 4ghz. Finished 24 hours of prime95 this morning with no errors. Now that thats done, i would like my processor to underclock itself when idle to save some power, no use browsing the internet at 4ghz. How do i go about doing this? I tried changing some settings in bios which i thought would allow the cpu to underclock itself but it just BSODs shortly after post. doesnt even get into widnows. Namely I enabled intels speed step tech (allows cpu speed to be controlled by the os) and enabled the C states (forgot what the actual option was called). So what did i do wrong? Or is there another trick or something im missing? Can this even be done or is it too high of an overclock to attempt any power saving?