So here I'm running a 2009 iMac. Great! Recently the HDD (Hard Disc Drive) died on it. Not so great. Luckily, I have all my files backed up periodically on an external drive. It's kinda nesaccery in this business. So being all tech savvy, I decided to save myself a LOT of money an install a non Apple HDD in it, and do the repairs myself. Simple enough fix. The iMac is pretty fiddly to open, and even more fiddly to replace the drive. New drive in, when I notice that by gum the official Apple drive has an EXTRA plug/socket on it with a wire coming out! Turns out this leads to a external Apple thermometer. No problem, I'll just put the drive in without connecting it to the Apple thermometer. Some of you know where this is going- starting up my computer the HDD fan wouldn't slow down, it was running at 5500rpm, and my HDD was at 30C. Too much either way.
Turns out that Apple computers run on that thermometer to regulate the temperature of the HDD. without information coming from that sensor, my iMac was panicking and making the fan run at full speed to ensure it didn't overheat. Even though it was actually really cool. So how to fix?
Well luckily HDD come with the S.M.A.R.T. interface these days, which means they all have an inbuilt thermometer and regulator! So all you really need to fix the problem is a program that will read and regulate the fan based on the S.M.A.R.T. readout. Problem solved. At present there are only two apps on the market which do this, and work on an Intel iMac.
HDD Fan Control is complete and works brilliantly but will cost you £20
SSD Fan Control will lower your HDD fan speed! And it's free! Win win! Unfortunately it only reads the SSD, not from the S.M.A.R.T. system. BUT he recently released an RC1 update that means it can read the S.M.A.R.T. interface. So email him for a trial.Be wary that it is development software, so you have to keep your eye on it until this gets a public release.
Word of warning: using an app to regulate the HDD fan speed will result in noisy computer startups. This is because the app actually has to be launched before it starts to take effect. Until then, your fan will be blowing at 6000rpm. Oh, and in ase you were wondering, my computer works like new again, thanks to Time Machine and backups.
