I have an Aerocool M40 and it's showing my HD activity pausing. At least that's what it looks like. It used to spin and spin not stuttering but now it seems to stop periodically. Is it the Aerocool's display thats wiggin out or my hd? I have noticed no change in performance from my PC. The only thing I changed was the cpu heatsink. I was looking for something quieter because the stock one spools up quite a bit when multitasking. It didn't overheat but the one got just sucked so I put the old one back but the activity indicator is still sticking?
Errrr... maybe your hard disk is just powering itself down to save power? How often is "periodically"? :P