I just sold my 17" MacBook Pro because I realized I hadn't taken it anywhere in a while and might as well get a desktop. I will be ordering a 27" i5 4GB/1TB. I got a 2TB Hitachi drive as a Christmas gift and would like to put it inside this iMac and put the 1TB drive that comes with it in an external enclosure. I would just order it with a 2TB drive if it were cheaper. As it is, the upgrade costs $225, which is $30 more than a 2TB drive on Newegg plus I wouldn't have the spare 1TB drive I'd have after the upgrade. So Apple really over charges for the 2TB drive. ~$30 plus the cost of a 1TB drive. It's absurd. /rant So I was reading this article on about.com about the hard drive upgrade and the troubles people were having with the new thermometers for the hard drives. http://macs.about.com/od/faq1/f/upgrade-hard-drive-in-late-2009-imac.htm Up until the new generation of iMacs, they just had a sensor that stuck to the outside of the drives, but now it uses a cable that reads the hard drive's internal, built-in sensor. Since hard drive manufacturers don't all use the same cable, each iMac comes with a different hard drive heat sensor cable. If the iMac is unable to see the heat sensor for the hard drive, it runs the fans at full speed all the time. So unless my iMac comes with a Hitachi drive, or a drive that has a compatible sensor cable, I'll either have to run the fans at full speed, not do the upgrade, or try and get a different drive by returning this 2TB Hitachi drive. Is there a way to modify the cable so that it will work with my Hitachi drive? I don't know much about these cables; I've never had a computer where the heat from the hard drive was something to worry about. I couldn't find any documentation about the heat sensor pin outs for any of the manufacturers Apple uses. Has anybody successfully upgraded the hard drive in their late 2009 iMac to one of a different manufacturer?