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My iMac’s hard drive ST31000528AS is dead and I need replacement drive. Can someone help me on deciding which I need. I have to buy these and I do not know if they are compatible. https://www.pcfactory.cl/discos-duros-pc… I have iMac Intel 21.5" EMC 2308 Model A1311 / Late 2009 / 3.06 or 3.33 GHz Core 2 Duo processor Update (05/08/2018) I’m worried about the third connector that is responsible for regulating the speed of transfer a 4-pin concetor to the bottom side of the cable is connected to the board also in forums indicate that regulates the speed of the internal fan of the mac so I need to know the compatibility since iriginal brought diso sata 2 and now there is a barracuda sata 3 https://www.pcfactory.cl/producto/25145-…
@jeff5000 - Jamie your system has a SATA II (3.0 Gb/s) interface so you do need to be careful on what drive will work in your system. A fixed SATA III (6.0 Gb/s) drive would not work reliably in your system so for starters lets push these HD’s aside as not workable. Now you can put in a fixed SATA II (3.0 Gb/s) drive but these are getting hard to find so lets put this option aside as well. Instead lets look at a different type of drive we call auto sense! These drives unlike the fix’ed speed drives have the ability to match up to the systems I/O speed. Thats what I would get here. So what drives are auto sense?. Here we need to look at the drives spec sheet to see what it has listed for supporting speeds. As an example the Seagate FireCuda Seagate Firecuda spec sheet lists supported SATA transfer speeds of 6.0/3.0/1.5. So this drive would work in your system. In addition as it’s really a SSHD it will offer even better performance than a traditional HD as the built-in SSD cache will make booting up zip and can improve application performance as well. As you noted there is a thermal sensor connection the (3rd cable). The problem is there are three different cables for the three different drives Apple had used (Hitachi, Seagate & Western-Digital). Today you can’t get the exact drives Apple used while some of the newer ones still offer compatibility with the pinouts as an example if you have a WD drive and replaced it with a WD drive you might get the sensor to work. Frankly, I don’t like the gamble and in this case WD does not offer a workable SATA II drive any more any ways. So what to do?? Well, it turns out OWC offers a nifty replacement that will allow you to use any drive! Here’s the cable OWC In-line Digital Thermal Sensor for iMac Late 2009 - Mid 2010 Hard Drive Upgrade Here’s the IFIXIT guide you’ll need to follow: iMac Intel 21.5" EMC 2308 Hard Drive Replacement
Jaime, any SATA based 3.5 inch hard drive will be compatible with your system. Do keep in mind you will have to reinstall MacOS onto the new hard drive after the physical installation is completed. Update (05/08/2018) The third connector on the drive is for the temperature sensing, most hard drives currently available will have the extra connector.
