Chosen Solution
I want to replace the HD in my late 2009 iMac. It’s a Seagate Barracuda 7200.12 1TB. Can I buy the same model on eBay, even if they don’t have the Apple logo on them? Will it be incompatible and cause my fan to run full blast? If so, is it possible to install the Apple firmware on them?
Yes! You can put in any 3.5" drive (and even a 2.5" SSD) in as long as its SATA speed is supported in your system. It does not need to be the same as what you have now (size or make). Your system has a SATA II (3.0 Gb/s) interface so the drive will need to run at this SATA speed. Review the spec sheet of the drive you are thinking on using and make sure it explicitly lists it. The next issue is the systems thermal management system (SMC). Your current HD has an internal thermal sensor the system accesses. At one point we recommended people get the same series drive (make & model) as the connection by the different drive vendors was different otherwise you would need to swap out the sensor cable to the other type. Today its more confusing as many drives don’t offer the same method of access so there is no thermal sensor cable that would work. Thankfully! OWC came out with an in-line thermal sensor which will replace the internal one. Here is the part you’ll need: OWC In-line Digital Thermal Sensor for iMac 2009-2010 Hard Drive Upgrade. You’ll need it for either a HD or SSD upgrade (swapping out your current HD with a different vendor or one that don’t offer the needed interface for the thermal sensor connection). Here is the IFIXIT guide you’ll need to follow: iMac Intel 27" EMC 2309 and 2374 Hard Drive Replacement and if you jump down the Step 10 you can see the sensor cable I’m speaking about here. But before we go down that path are you sure you need to replace your current drive here? Maybe all you need to do is swap out your current optical drive for a 2.5" SSD or HD to give your system some zing and/or more storage! Here’s the IFIXIT guide you’ll need to follow for that: Installing iMac Intel 27" EMC 2309 and 2374 Dual Drive
