I have a 20 inch 2.66 aluminum iMac that came with a 320GB HDD. Lately the HD seems to grind for a long time when I launch any programs. The whole computer seems to just be waiting on the HD to catch up. I have 4GB of ram and it never uses all of it but I can hear the drive reading/writing while I wait for apps to load. Most notably safari, cs4, etc. but it does happen on many other programs. I thought that the issue was that it had been going on a year without a reformat, I waited until snow leopard came out and completely wiped the drive and installed 10.6 on it. However the slowness came back and I have since formatted again only to have the same problems. Has anyone else experienced these slow HD's? I have run Drive Genius on it and there is no bad blocks/SMART is verified.