Your PSU looks sufficient, so whilst it could be possible that it is causing your crashes, it would not be my first port of call.
I would start by using DDU to remove your current drivers, and then updating to Crimson 17.2.1 to see if that resolves your crashes. If they persist, unlock Wattman and set the Power Limit to +50% and click apply. Recheck the issue status.
If the same issue occurs, then try lowering the core clock by 200Mhz and see if the same issue occurs. If the crashing stops, your GPU is most likely faulty. Try it in a different system.