so i started the thread about the noise of the hard drives, particularly Seagate's making the grumbling. After having so many replacements and also trying the 2TB hitachi all made this noise, so i left the iMac for a while and used my 15"MBP and last month i decided to go for it again and also ending up with a seagate, i tried to live with it and couldn't so decided to crack the thing open and put in a 2TB Western Digital (had to wait 2 weeks for the sensor cable) swapping it over was a doodle and also getting SL back on was a breeze. THE VERDICT.... Still *@%*ing noises!!! to be honest not as bad as the seagate and i can definitely live with it better. For everyone thinking they have faulty drives etc you clearly have not and i am now 100% convinced the aluminum backing is clearly making the noise and amplifying it. on another note this Western Digital drive i have put in seems alot quicker than the Seagate, temperatures are very good and fan speeds normal, so i am a lot happier!