ive just applyed some to my cpu now, and tbh its dropped a couple of degrees instantly, pleasantly
with the stock amd fan flat-out it would sit around 35/36 deg's idle and 37/40 maxed (fans all at full speed).. but i replaced it with an arctic cooler 64 pro so it didnt sound like a hoover on steroids
i only had cheapy thermal grease when fitting the a/cooler as most of the stuff on the new h/s had been smudged in transit? somehow...
it then started to sit at 40 deg idle (fans low for audio/dvd), 46/47 (fans full speed) flat out and now o/c'd at 2.485.0 so i thought id give it a go to get the temps back to original without all the fan noise.. possibly!?
been on an hour running and it now sit's at 36/37 idle and 43/44 under load.. its supposed to get better after a 200 hr burn in with cool down pauses, with an added 2-5 deg drop.. we will see (hopefully) but its more than worth the few pounds/dollars it cost anyways and might be handy for very high temp o/c's if a degree or three is causing issues i guess..
3 deg's lower with no added noise is good for me anyways..