I have a circa 2008 24" iMac 2.4Ghz and recently had my HDD professionally upgraded to a SATA 1TB WD Caviar Black (CB). My problem is that after about 2 hrs and 15 min, the drive begins to “humm” - no clicking noise, no loss (so far) or change in performance, but the humming sound is pronounced and annoying. In reading other posts, I understand that the CB is a high performance drive and may run a little hot, but I’m concerned with the constant noise. By listening to the back of the iMac, it is not the fans (they are not that noisy) - it does sound the like the drive.
Any ideas or suggestions would be appreciated.