Juju

Ever since I got this MacBookPro (15" Rev A. 7200 RPM HD) I had noticed the harddrive makes a "clunk" sound. Not really a click, it almost sounds like a marble dropping on a table. Coincidentally, some things like youtube videos would periodically freeze for no reason. I had tried all kinds of things over the years and nothing helped. People in forums have talked about it, some said it's normal, some said your drive is about to die. Well I just found hdapm!

I used that to set the APM (power management) to max performance and all my problems have gone away. Some tasks even seem a little faster, but it could be my imagination. Apparently, the OSX power management "better performance" doesn't really set true max performance on some hard drives. What was happening is the read head was periodically trying to park even when disk access was happening. So it was parking and then unparking right away. It does that to try and save power. Well my laptop is almost always plugged in, so I don't really need that.