It has not been too long since i built this rig but I have been experiencing the same problem occasionally. I will either be watching videos online or gaming and occasionally experience the following message on Windows 10 "Your PC ran into a problem and needs to restart". At other times the computer will shut down but however the led lights on the fans and the fans will still be running. THen i may even get a red blank screen very rarely as well. What could be the cause of this? I have overclocked my computer to 3.7 ghz at 1.2v just in case you need that and it also passed the stress test. I have seen the recommended psu is 750W for r9 280x but i currently only have 550w. Could this be the reason? Here are my specs:
cpu: ryzen 7 1700
gpu: powercolor r9 280x
mobo: msi b350 tomahawk
psu: evga g2 550w
ram: g.skill 4 series 3000 mhz running at 2800 mhz
operating system: windows 10 professional
ssd: crucial mx300 275 gb 2.5"
HDD: WD 7200 rpm 1 TB
peripherals: g502 logitech mouse, razer kraken 7.1 chroma headset, reddragon mechanical keyboard
monitor : HP 27 inch
cpu: ryzen 7 1700
gpu: powercolor r9 280x
mobo: msi b350 tomahawk
psu: evga g2 550w
ram: g.skill 4 series 3000 mhz running at 2800 mhz
operating system: windows 10 professional
ssd: crucial mx300 275 gb 2.5"
HDD: WD 7200 rpm 1 TB
peripherals: g502 logitech mouse, razer kraken 7.1 chroma headset, reddragon mechanical keyboard
monitor : HP 27 inch