I'm using Windows 8.1 with an external hard drive. My external seems to go to sleep very quickly, like in a single minute. I constantly wait 2-3 seconds when accessing files on my external harddrive (where all my important stuff is). I have not had this problem on other OSs with this same external HDD.

I checked my power settings, its supposed to wait 40 minutes before spinning down (on battery and plugged in). This is clearly not happening. What might be the problem here?