Problem with pc freeze

I recently bought a used GPU but in very good condition. but after playing in more demanding games when gpu reaches 100% use, suddenly the pc freezes and the card turns on 100% fan speed but temperature is still ~37/39 C, and I think that this may be a problem with the power supply because it supposedly has the 650 W, but often I had problems with it before. and here's the specification

i5 8400, asus strix gtx 1080, 8GB ram, asrock b360 pro4 and coolermaster gx 650W power supply

Try upgrading the powe supply. If that doesnt fix anything you can try water cooling + fans. Let me know how you solve it Im curious

maybe it is strange but I bought a new case this morning and the computer did not freeze when I play demanding games

You should check your Hard Disk it may cause freezing problems

Are you sure it isnt something to do with the RAM cause when i upgraded my ram it stopped doing this

Download the logiciel malwearbit, is the bestest logiciel for the virus and problem with the ram (freeze)

You should swap each part to see which part is giving issues. Generally is RAM or the PSU (under powered).