Question New PSU dead after 30 minutes. Possible cause?

[A Hamburgl3r]

To make a long story short I got my new 3090 GPU and a liquid cooler for my CPU. I install the new 3090 and my pc would shut off under load. At this time I was running at 750W EVGA SuperNOVA PSU. I failed to check the power requirements of my 3090 which recommends 850W. I go to my local bestbuy and get a get a Corsair RMx RM1000x 80 plus PSU. I install the new PSU along with the new liquid cooler and everything is good. No issues under full load and all the temps are good. After 30 minutes of playing games my PC shuts down. This time it wont turn on. I plug in the old 750W PSU and again nothing happens my PC does not turn on. At this point I'm thinking the motherboard is fired. My last resort was to swap the new Corsair wires for the old EVGA wires. When I tried this I tried it with my 750W PSU and my PC gained life. I then try the Corsair PSU with the old wires and it did not start. To double check I installed the new Corsair wires again and tried the 750W PSU and again nothing happens. I go back to the EVGA wires and my PC turns on.

So my obviously my new Corsair PSU is fried along with its wires. My question is do you guys think it was just a faulty PSU or could something be causing this. I am now currently using my old 750W PSU and just had to turn the power target for the 3090 down. I'm debating on getting a replacement Corsair PSU or just getting a refund and ordering another PSU. Again what do you guys think?

My Specs.
MSI MPG Z490 GAMING CARBON
Intel Core i7 10th Gen - Core i7-10700K
ASUS TUF Gaming GeForce RTX 3090
ASUS ROG Strix LC 240
Corsair 32G RAM

 

[SkyNetRising]

My last resort was to swap the new Corsair wires for the old EVGA wires.

Modular cables are not compatible between different PSU models.
By using wrong modular cables you have killed your hardware. Never do that.

 

[A Hamburgl3r]

Modular cables are not compatible between different PSU models.
By using wrong modular cables you have killed your hardware. Never do that.

So when I installed the new Corsair PSU I used the wire that came with it but it still died. So that's definitely not what killed it.

 

[Juular]

My last resort was to swap the new Corsair wires for the old EVGA wires. When I tried this I tried it with my 750W PSU and my PC gained life. I then try the Corsair PSU with the old wires and it did not start. To double check I installed the new Corsair wires again and tried the 750W PSU and again nothing happens. I go back to the EVGA wires and my PC turns on.

You've killed your hardware by using wrong DC cables. A Corsair PSU wouldn't work with EVGA cables, so you've likely mixed them around and were using EVGA cables first and then swapped for Corsair, that's why it worked out, then swapped to EVGA again and killed the hardware for real.

PS: Corsair cables have 'PCIe' written on well, PCIe cables, EVGA ones would have 'PCI-e'. No idea for 24-pin ATX and EPS tho.

 

[A Hamburgl3r]

You've killed your hardware by using wrong DC cables. A Corsair PSU wouldn't work with EVGA cables, so you've likely mixed them around and were using EVGA cables first and then swapped for Corsair, that's why it worked out, then swapped to EVGA again and killed the hardware for real.

PS: Corsair cables have 'PCIe' written on well, PCIe cables, EVGA ones would have 'PCI-e'. No idea for 24-pin ATX and EPS tho.

Ok so ya that's bad and I wont be doing that again. But as I stated when I first installed the new PSU I removed all the old wires and used the wires that came with the new PSU. That same PSU died after about 30 minutes and I was wondering why exactly a PSU would die like that.

 

[--SID--]

That same PSU died after about 30 minutes and I was wondering why exactly a PSU would die like that.

99% of the cases it's an user error...somehow.