Wat can I do to get rid of sudden power off?

I often have my pc suddenly switching off  in a hour or two of Realty Capture working. Usually during any  heavy job of more than 100 photos.      I suspect it’s during  high GPU usage stage since once it goes to CPU  for mesh building  or something it proceeds and finishes just ok .

I suspect it’s my 500W PSU might be  still not enough  for my GF980ti   Still  Octane render never makes  same things for example . Neighter  Metashape  which calculates depth maps on GPU too (but much slower )  nor any other gpu using soft.

So I wonder what can I  still do without all the PSU  or videocard replace hassle?  Considering I couldn’t buy a  new videocard for many month already.    I have some “Aorus engine” utility where I can make GPU fans to rotate with an insane speed  or dampen GPU frequency for a few % .   Should it help?  

Yes, there can be some problems with over heating, so the higher speed of fan can help. But 100 photos is not such a big number, so I would consider to buy a new machine with better parameters. You can check this site with recommended setup: https://www.pugetsystems.com/recommended/Recommended-Systems-for-RealityCapture-228/Hardware-Recommendations