Question I finally built a new PC but any graphics card which needs auxiliary power just keeps crashing ?

Nov 16, 2021
I recently made a new pc using a pack bought from ali express containing a xeon e5 2620 v3, a x99 8mf motherboard, 16 gb of ram and i put in an old videocard, an amd r9 270 with 2 pci e adapters and a corsair cv550 psu. After 4/5 days of gaming i started to experience random crashes, particularly after quitting the game or completely random. The crashes were more like freezes and they soon became much more troubesome, and eventually I couldn't play any longer.

I thought that the graphic card was the culprit because my old gt 440 worked without problem with this setup, so i ordered a new one, a gtx 970, removed all amd drivers, updated with the nvidia ones and started playing, after 10 minute of a very good performance the game locked again in the same way, with desktop shutting off. So i thought that the psu was the culprit even though 550 was fairly ok with the 970, and i bought a new psu with 750 w. It didnt get better at all, even worse, and while in the beginning it was closing after 5 minute of furmark as times passed and after some testing i am now able to play furmark for no more than 10 seconds withouth crashing, as if windows is just automatically crashing now.

Still, my old gt 440 which does not need auxiliary power from the PSU, that works without problems. I would like to point out that the person who advised me in building this pc actually tried overclocking my cpu by downloading a turbo version of the bios and by flashing it, we even had some problems in discovering the chipset so we may have downloaded and applied the wrong version, i have to say that this didnt better or worsen the situation, but it may be something which the more knowlegeable of you may be interested in, even thought we reset everything back to the original.

Tested the gtx 970 on a friend pc on a very demanding game and it didnt crash, so i think i can rule her out maybe, and i bought two new psu way over the power limit requirement one after the other, so i would rule them out too, or im the unluckiest man in the world.. What else could it be? Are there some settings in the bios that can change the wattage from the PCIe power cables?

I can see this as the only reason for crashing, as the graphics card which does not need any PCIe power cables gives no problems at all ?