Disk Usage 100% Win 8.1

[YellowGuerilla]

After noticing a performance drop and overall slow speed, i opened task manager to find disk reading at 100%. of the Four Programs running, im transferring less than 3 MB/s. What is causing the disk to be at 100% usage? Ive been looking around, but not finding any good answers through google.

 

[YellowGuerilla]

I found a defrag running in the background. Disabled them from happening in the future. Thanks anyways.