Some hard drives produce annoying clicking sounds when idle. If you experience this problem with your Mac we have the solution for you. With some hard disks the read / write heads are repeatedly loaded and unloaded when the drive is idle. The easiest fix is to set all hard drives to maximum performance, but this also affects the operating time of your Mac, because it makes the hard drive run all the time and it of course draws power from the battery to do so. But there is another fix for this problem.
The solution is called hard disk advanced power management (hdpam) and can be accessed from the Terminal. First though you need to install the hdpam command line utility by Bryce McKinlay which can be downloaded here.
With this utility you can set the suspend time for your harddrive to your desired value. This utility is the same function as the check box ‚Put the hard disk(s) to sleep when possible‘, but instead of only being able to switch it off or on, you can set it to your desired value between 1 and 254. This will eliminate the click sound and still save power so your battery will last longer. A detailed instruction can be found here. If you are using this tool with our hardwrk adapter kit and have your SSD, as recommended, in the regular HDD slot, make sure you select the right device (disk1 instead of disk0).