PC restarting randomly without any warnings

[technet.sudipta]

Good Morning everyone..
So I salvaged my old PC.

The Specs are:
AMD A10 6800K
MSI A88X-G45 Gaming Motherboard
12 GB DDR3 Ram (8+4 GB)
GTX 1050ti (Bought Recently)

So my pc restarts randomly on Windows 10 without any warning and the CPU usage on Task manager peaks out most of the time. After every restart, I tried troubleshooting but failed
- I tried removing the graphics card once and for all
- I cleaned the PC
- Gave it a fresh installation of Windows 10
- Bought a Liquid cooler for the CPU
- Tried replacing the RAM slots..
*And another problem, Out of my 12 GB Ram, I only get 7.2 GB shown on the task manager and the rest shows to be consumed by System resources and while usage I only get 50% of the 7.2 GB -_- *

Can anyone please send some help? It would be appreciated

 

[Calvin7]

A10-6800K supported memory: DDR3-2133

Memory is guaranteed in the form it is sold in. No guarantee for compatibility with unusual combinations such as your (8+4 GB) combination. You can do your own compatibility testing.
Kingston HyperX FURY Black 8GB Kit (2x4GB) 2133MHz DDR4 Non-ECC CL14 DIMM Desktop Memory (HX421C14FBK2/8)
https://www.amazon.com/Kingston-HyperX-2133MHz-Non-ECC-HX421C14FBK2/dp/B00TY6A1P0

 

[Guest]

Hi,

Can I know make of your ddr3-ram like corsair,g.skill,kingston? Also tell me make of your psu like seasonic.?

Seems like bad ram or psu.