In this article, we will address issue of Apple iMac fan noise running constantly at full speed after hard drive replacement or hard drive upgrade.

If your Apple iMac computer has hard drive replaced or upgraded recently and you notice that the computer fan is noisy at all time, the fan appears to be running constantly at full speed even though there is little activity in the computer, this indicates that the computer fails to read temperature from the new hard drive. This is common for older Apple iMac computers (prior to 2012 models). This is not a major concern. To put this simple, the new hard drive might be “too new” and thus not compatible with temperature sensor of your Apple iMac computer. The computer then assumes that the new drive is over-heated and instructs its hard drive fan to run at full speed causing the loud noise.


Fixing this problem is easy by installing a small app called SSD Fan Control.

This app can be downloaded from our website by clicking on this link, or from the developer website at

How to use it

  1. Download the package
  2. Run the installer (reboots your iMac after finishing). Allow it to open in System PreferencesSecurity if required.
  3. Run the SSD Fan Control application
  4. Find the noisy fan and click on ‘SMART’ mode
  5. You should notice the quietness of the fan instantly