[SOLVED] PC won't boot after installing GPU - 3080 FTW3

ctgunner

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Hi Everyone,

EDIT: Thank you everyone for your help, I learned some things about PSUs and am happy to report that despite my mistake the GPU is operating fine and the system has been booting without issue.
  • Had a minor issue with stuttering/mini freezes the first couple of boots but that appears to have resolved as well.
So after building my new PC i have the following problem:

When i install the GPU the motherboard/fans won't power on, only the RAM RGB will light up.
  • When I remove the GPU all the fans/MB kick on.
Is this a power issue or is the issue that it's depressing the F_32 (USB 3.2 Header) too much - its depressing it quite a bit. How do I tell, and is there some sort of adaptor i can get for this connection if that's the issue?

Parts:
Aorus B550m Pro-p
RTX 3080 FTW3
Ryzen 5600x CPU
Seasonic Focus PX-750 Platinum PSU

Case:
Meshify C Mini
 
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I had 3 individual 6+2 cables running to the gpu from the power supply. Idk if it matters but the power supply i bought didn't come with ANY which i thought was odd and they came from a g3 850W PSU i used on my first ever build.
You cannot mix PSU cables like that. The cables you use has to be from the PSU you use.

You can damage your hardware.
 
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ctgunner

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Are you using 3 actual PCI-E GPU connectors from the PSU to the GPU. Not daisy chaining them off the same connectors?
I had 3 individual 6+2 cables running to the gpu from the power supply. Idk if it matters but the power supply i bought didn't come with ANY which i thought was odd and they came from a g3 850W PSU i used on my first ever build.
 
I had 3 individual 6+2 cables running to the gpu from the power supply. Idk if it matters but the power supply i bought didn't come with ANY which i thought was odd and they came from a g3 850W PSU i used on my first ever build.
You cannot mix PSU cables like that. The cables you use has to be from the PSU you use.

You can damage your hardware.
 
Reactions: ern88

ctgunner

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It's probably fried TBH. Wrong pin layout means power going to wrong connections on the GPU.
Well thats a huge bummer, so in this instance, the PSU I got didn't have the necessary cables - where would i go to ensure i have the correct ones next time? Is there a way to check the GPU? Should i try installing it in the old PC or would that risk additional issues?
 
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Phaaze88

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That unit should've been supplied with TWO, pigtailed(I'm not sure that's the correct term) 6+2pin cables.

Since they are missing, you would contact the manufacturer(Seasonic), let them know that those cables were missing, and they should send you some free of charge.
 

ctgunner

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That unit should've been supplied with TWO, pigtailed(I'm not sure that's the correct term) 6+2pin cables.

Since they are missing, you would contact the manufacturer(Seasonic), let them know that those cables were missing, and they should send you some free of charge.
My understanding is that even with 2 that should've come with, I would need to order a 3rd? Looking at the manufacturers website on first glance that doesn't appear to be an option?
 

Phaaze88

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My understanding is that even with 2 that should've come with, I would need to order a 3rd?
Unfortunately, there's no official statement from manufacturers on that - instead there's a bunch of 'they said this/that'.
It's widely agreed to use separate cables if at all possible, then use the pigtails.

Looking at the manufacturers website on first glance that doesn't appear to be an option?
So it has two cpu EPS(4+4pin), and two pigtailed PCIe 6+2pin.
On the actual psu box, it has a 5th CPU/PCIe port... why it's there, even though only 4 cables are supplied for that, I've no idea.
 

ctgunner

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Unfortunately, there's no official statement from manufacturers on that - instead there's a bunch of 'they said this/that'.
It's widely agreed to use separate cables if at all possible, then use the pigtails.


So it has two cpu EPS(4+4pin), and two pigtailed PCIe 6+2pin.
On the actual psu box, it has a 5th CPU/PCIe port... why it's there, even though only 4 cables are supplied for that, I've no idea.
I really appreciate the help but would it be worth it to try installing the 3080 in my other PC since that uses the same power cables to see if it works or would I be risking damage to those parts too?

This is all new to me. It never would've occurred to me that power cables aren't just power cables. So apologies for the endless questions.
 

vov4ik_il

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Well thats a huge bummer, so in this instance, the PSU I got didn't have the necessary cables - where would i go to ensure i have the correct ones next time? Is there a way to check the GPU? Should i try installing it in the old PC or would that risk additional issues?
First, most here will not recommend it.
Yet I believe it is completely harmless and you have absolutely nothing to lose.
Just use the diagrams of your PSU pinout (link) and rearrange pins on your connectors so that the PSU side matches your new PSU. The pins are easily extractable with a fine flat screwdriver.
 

ctgunner

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Don't do that with modular power supplies. They're not universal(pin layout).

Highly likely you damaged something.
I'm happy to report that the GPU is functioning fine currently and I finally have got the system to boot/have successfully played a game on it.

The cable management for the GPU is hideous, and can't really be fixed but hey, it works.

Thanks for all your help, learned something new today.
 
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ctgunner

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What exactly did you do?
Picked up the same PSU from the local store, it had the 2 pig-tails included. While not cheap, nor intuitive, it seemed like the easiest solution to see if the included pig tails would power on the GPU to establish if I had in fact ruined it or not. It's a giant knotted mess, both connections on 1 cable, and 1 in with 1 hanging off on the other. They aren't braided either so it looks extra trashy, although I don't know if I could've got both in on 1 cable had they been.
  • Had some minor freezing/stuttering on my first 5ish restarts but it has gone away, and I'm assuming updating all my drivers was what resolved that issue.
Only tested it in OW so far but at Ultra 1440p@144FPS never went over 67C. GPU Idles at 39-40C.

For anyone who may be interested this is my entire parts list:
  • Aorus B550m Pro-P (F10 BIOS out of the box, haven't flashed to the newest)
  • EVGA 3080FTW3
  • Ryzen 5600x
  • Sabrent 1TB RocketQ M.2 (works as advertised)
  • 2x16GB Trident Z Neo 3600/16 (XMP Profile worked perfectly)
  • Seasonic Focus PX-750 Platinum
Only reason I went with this PSU was because it was the best available at the time, and was the only missing part left. PSU itself works great as far as I can tell, but for the price the [sometimes] included cables should be way better. Coming from the EVGA G2 850+Gold, that came with 4 individually braided 8pins really highlights just how <Mod Edit> these really are. In hindsight, I should've just ripped out the G2 and found a different PSU for my old PC. Live and learn.

Case:
  • Meshify C Mini (dark window); stock fans removed. Using [Corsair] 2x140mm Front intake, 120mm Exhaust. Have the 2 extra 120mms it came with if I need them but temps seem fine.
  • Noctua U12S + extra all-black noctua 120mm Fan on the back, and chromax shroud over the radiator.
CPU idles at 32-34C, and I haven't seen it go over 45C during gameplay. (it is not currently OC'd)
 
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