Hi guys!
 
First, sorry about my english.
I have an GTX960, when I'm playing some 'heavy' games (like DotA), sometimes the complete system shuts down. No blue screen, no errors. The energy supply just go off. Like a shortcut or like if someone unplug power cord.
I already change for upgrade:
CPU -> Ryzen 5 3600
Motherboard -> Asus prime B450M-A
Ram -> 2x8 3200Mhz Viper Gaming
Power supply -> Cooler Master 650 bronze.
 
And the problem is still there.
Temperature is fine. I make some mainteinance, like clean vents, blow off dust and change the thermal paste.
 
I have some oil from the pads spread, but I read that is common and harmless.
 
Any leads on this?

I had a similar issue with my GTX 970, not sure if its power supply because I had a 750w Plat (new) and it still went out

Having a very similar issue with a r5 5600X and a GTX 970 SSC. Everyone likes to point to the power supply but that is simply not the case as I had a 3080 in here for a while and it never crashed or went straight to reboot like this does. I am also having weird issues like audio cutting out, random reboots even when idle, etc. Once again it is definitely the GPU as it never did any of this with the 3080. I believe it is a problem with the way AMD chips talk to the 970, maybe requesting more memory (3.5GB scandal anyone?) than it really has.

also make sure your cable's connector are exposed anywhere in the case.... it might cause a short
 
maybe its a good idea to recheck all your connections

try replugging the cables from gpu to psu. sometimes they get loose