Question system shutting down

Jun 13, 2020
I've recently upgraded my gpu from an XFX Radeon R7 360 to a PowerColor Radon RX 8GB. Ever since I have my computer shuts down during games like Guild Wars 2 and Fortnite.
I've tried reducing graphics settings and it still happens after the computer has been on a while (even just playing Roblox).
I've reapplied thermal paste to the CPU and completely cleaned out the system and bought extra/replaced old case fans and none of this seems to have helped.
Is there anything else I can try before upgrading my motherboard and CPU.

PSU: Ace 650W BR Black PSU
CPU: AMD FX-6300 Six Core CPU
GPU: PowerCore Radeon RX 580
Motherboard: Gigabyte Ultra Durable 990X-GAMING SLI
SSD: Barracuda 500GB w/ clean install of Windows 10pro
that Ace 650W BR Black PSU is a £25 PSU maybe you should upgrade it to something a bit more powerful for that RX 580,4229.html
Evga g2/g3
Seasonic focus/prime
I would recommend an EVGA SuperNova Gold G2 / or new G3 /GS / GQ, Platinum P2 / PS, or Titanium T2 or a Seasonic M12-II Evo or S12-II
GOOD PSU EVGA is a B2, G2, G3, P2, GS, PS, or T2. Avoid the EVGA B1 and G1 series/ I bought a EVGA G3 with 7year garentee
May 19, 2020
I would try a new PSU before upgrading your entire system - I'd also recommend checking the temperatures if you haven't already (software like coretemp or GPU-Z). If your system is just shutting down randomly the usual suspects are temperature or power issues.

Tdlr; Check your temperatures to see if it is overheating, get a new PSU.