Suddenly my computer using High Memory and 25% of CPU

[Sovik]

From yesterday I'm facing this issue. I have 4GB DDR3 Zion RAMS 2+2.

Today I formatted my O.S because of this but still facing this issue. So, just now I uninstalled ESET Smart Security and my RAM become normal but I'm using ESET since 4 years then why suddenly getting this issue ??

Also planning to upgrade 8GB RAMs. [Corsair CMZ4GX3M1A1600C9 Vengeance 4GB + 4GB]

My Computer Specifications:-

i3-2120 Intel Processor.
DH61WW Motherboard.
ZION 2GB + 2GB 1333MHz RAM.

Should I upgrade ?

 

[kacpercusen]

it must be a program in the background press ctrl+alt+del got to task manager and proccesses and see if there is anything unusual there