PC tripping out when gaming. Power consumption or heat?

My PC has been completely tripping out within twenty minutes of playing a game. It varies a lot between games. Thinking it was the CPU, I replaced the thermal paste. It tends to run no higher than 85 degree's Fahrenheit. According to AMD Overdrive, the thermal margin is pretty much always at 8 degrees Celsius (Even when I reduce the clock and voltage massively. Usually when I start playing, it slowly creeps up tp 17 degrees and then the computer completely shuts off. I've opened the event viewer, and it only notes that the PC shut down unexpectedly. No other information provided. My PC is plugged into the wall, not a power strip.
Specs:
AMD RX 480
FX 8350
Old ass 8gb ram (Total ram used doesn't seem to correlate with the system shutting down. Ram speed might be)
Windows 10

If I reboot the PC too soon after it tripping, it will trip out again immediately. Is that a high-temperature symptom?

 

I did consider that. 17 degrees seems a bit low for the whole thing to trip out. So I lowered the voltage and clocks on my GPU and CPU, thinking that it might reduce the load on the PSU, and it was still tripping. Is there anything I can do to accommodate this PSU without replacing it? And is there something I can do to figure out for sure that it's the PSU before I make purchasing decisions?
I used an online calculator and apparently my PC doesn't require any more than 550watts and I currently have a 650watt PSU. Could it just be faulty?

 

Wow, I had no idea. Thanks