Question low end PC but want to improve

[gearism]

this is my spec

Intel(R) Core(TM) i5-6600 CPU @ 3.30GHz 3.30 GHz
gigabyte h110m-ds2
Kingston 8gb DDR4 2133 MHz
RX480 8GB
samsung ssd 860 evo 500gb
corsair TX 650w power supply

i know all these are low end setup and i need to know what to improve and solve some problems with it for examples

1. the cpu always load on 100 percent when playing game and open the browsers at the same time, should i need to upgrade ram?
2. pc restarted when playing games, this only happen like twice a month when i really push it

i also have a limited budget but problem 1 really is my concern
if you need more information just ask...thank you all

 

[ThatVietGuy]

It helps to know what this budget is in precise numbers...

 

[gearism]

It helps to know what this budget is in precise numbers...

i live in malaysia so around rm1000 or 250 dollars