Instructions.
Open CDI(CrystalDiskInfo)
-Select your drive. It is easy as selecting the drive letter of the new drive(you will see the WD20EARX number).
-Click the
Function menu then select
Advanced Feature then select
AAM/APM Control
You will get a new screen. Disable APM from here. You can check by going back to that screen to ensure it has disabled, but it should have on the first try.
You may see that I have 2700 load cycles, that is in just under 30 days of use.
If all is well, The drive should stop getting more LLC(Load/Unload Cycles) and no longer click. on reboot the drive will start to click again. I know this sucks, but at least it tells you it is the power management causing your noise.
If your LLC is less then 100-200 a day, chances are the drive will still have a long like(5+ years).
WDIDLE3 is an option, but many recommend never fully disabling the idle park and setting it to 300 seconds. This will most certainly be frowned(warranty voiding) on by WDC as they did not make this software for your drive.
Other users have made a script or program that writes a small bit of data to the drive every 7 seconds to prevent sleep.
Some users are also reporting that WDC has stopped logging LLC as it was making customers worry too much(seeing something jump by 100+ a day when the old drive only jumped by the same number as the number of system power ons for the day). Not sure, the drive in my image logs it and is a laptop drive(I wanted quiet and its llc are still quiet for the most part every now and then it is loader then I like in a media pc).
If you need more info, let me know.