Question No power when gpu plugged.

[S.vincent]

Hello.

im facing a bit of problem in my new pc build. The power wont turn on when the gpu is plugged to the power supply. When i unplug the gpu power cable and turn on, the power goes to the whole system(fans,ram,cpu pump..etc). I have tested the gpu in my old pc and it works and turns on. So the gpu works fine. And since the power supply turns on when gpu unplugged im assuming the power supply also works fine.

Both power supply in this new build and the old one are 850w. The new one how ever is an sfx cooler master 850w. Its a brand new powersupply

have done cmos reset, bios update etc on the new system. It doesn’t work. And also have tried with another gpu as well in the new system and still not working. Both gpu works fine when checked on another system.

i tried to use this new powersupply on my old pc and the same happens. But when the graphics card is removed old pc also fires up and turns on. But with the old power supply everything works fine. So i used the old powersupply on the new system and it turns on now. So whats wrong with this new power supply? And why does it only stop working when the gpu is plugged in. 850w is more than enough for both systems.

here are my part lits

amd ryzen 5950x
Gigabyte Aourus pro motherboard
Corsair vengeance
Rtx 3090 asus tuf
Cooler master sfx 850w

 

[helpstar]

did you plug in both motherboard ATX connectors to the PSU? 18 pin and 10pin

are you using the original cables which were delivered with the new PSU or are you using the old ones?
take some pictures and upload to imgur

 

[S.vincent]

did you plug in both motherboard ATX connectors to the PSU? 18 pin and 10pin

are you using the original cables which were delivered with the new PSU or are you using the old ones?
take some pictures and upload to imgur

oh thank you kind sir. Your comment make me check all cables. The sfx powersupply came with very short pcie cables for the graphics card and it was not reaching so i was using an extra long cable from an ATX psu. I switched to the short cable and added an extension cable and now everything works. Thanks again. Im a newbie so it was my mistake.