Windows should use all available RAM, even for a trivial purpose. I can't guess what's running at the time so you'll have to use task manager to see if you can find it.
However you have IOBIT which is pure junk. I would not accept your machine at the shop counter until we got the go ahead to wipe the drive and start fresh. It's that bad.
8 Gb Ram
AMD FX(tm)-6300 Six-Core Processor 3.50 GHz
AMD Radeon HD 7700 Series
So i built my computer december of 2015 and it started having this problem about 4 months ago where i would be doing something sometimes nothing and on my iOrbit Advanced System Care Preformance Monitor my ram usage will go from around 4.50 (when gaming) to 7.50 out of usable 7.90 and my whole computer slows down and it sometimes goes down after around 3-6 minutes but i usually just hit the reset button on my PC and its fine for about a hour. Please help and thank you