Was it my graphics card, power supply, or something else?

[KizenTech]

So about 2 months ago I decided to build a computer and everything worked completely fine. Just a few days ago while playing a game the whole system shuts off by itself. I frantically try pressing the power button again hoping the entire system would turn on but I had no success. So I open up the system to find what is wrong and here's my problem: My GTX 1070 FTW has 2 6+2 pin cables going from the graphics card to the power supply. Whenever I take the cables that connect the graphics card and the power supply out and power on the system, everything seems to work fine but with the cables connected to the power supply the whole system would never turn on. In fact the only thing that would happen when I hit the power button is my fans light up and then immediately turn off (RGB fans). I have sent an RMA to EVGA about my graphics card and am in the process of receiving a new or refurbished one but doing some searching around on the internet has concerned me. Some forums have reported the power supply or motherboard being faulty, while others claim it's the graphics card (although no one seemed to have the EXACT same problem). So was I wrong to assume the graphics card as the culprit or should I suspect the power supply?

 

[CountMike]

You didn't say which PSU, it's possible that it was at it's limit power vise and now it either got weaker or lost power on 12v part. Unfortunately only way to troubleshoot things like that is to start swapping parts with new, known good parts.
If your MB has graphic output you can try taking GPU out and trying that.
Another thing to try is to switch GPU to another PCIe port if possible.

 

[KizenTech]

You didn't say which PSU, it's possible that it was at it's limit power vise and now it either got weaker or lost power on 12v part. Unfortunately only way to troubleshoot things like that is to start swapping parts with new, known good parts.
If your MB has graphic output you can try taking GPU out and trying that.
Another thing to try is to switch GPU to another PCIe port if possible.

My PSU is an EVGA 650 80 plus gold. Sadly my motherboard does not have a graphics output and since this is my first build and I come from a family of apple users I do not have any spare parts to test with. I am getting the replacement GPU from EVGA's RMA department so that's pretty much the only way I can know for sure that the issue was my graphics card. But I've been thinking that if I hook up the card and my pc still refuses to turn on, to RMA the power supply. But before doing an RMA (if the GPU replacement doesn't work) I wanted to confirm that it could most likely be an issue with the PSU.