Question Not enough power for 2 GPUs?

[Hallusion]

I'm attempting to run 2 GPUs using a 1000W power supply. Works fine without the 2nd GPU, when I attach the 2nd GPU the PC won't turn on. Pressing the power button only causes the RGB RAM to light up, fans don't start, no other indication of being powered on.

Details:
PSU: Apevia ATX-PR1000W PCIe 5.0
1st GPU: NVidia GTX 1660 Super
2nd GPU: NVIDIA Tesla K80
Mobo: Gigabyte Z790 UD AX

Only thing I can think of is the PCIe 5.0 cable is designated 600W which could maybe imply only 400W available for everything else, but that seems like hopefully not how that would work...

 

[helpstar]

Did you plugin the power plusg to the 1st and 2nd gpu?

did you try each gpu seperated?

update the motherboard's bios

 

[Misgar]

The PCI Express 5.0 12VHPWR cable can supply up to 600W to an appropriate GPU card, but if you're not using this cable on your Tesla K80, the 600W of power does not magically disappear, but is still available on the other outputs.

Can you confirm the K80 uses 1x8-pin PCIe power, not 12VHPWR?

Check your mobo BIOS and see if it allows you to install two GPU cards. You may need to define which is the primary (main) card for Windows(?) to use at boot up.

Does your CPU have built in integrated video, adding a third GPU to the mix? No wonder the system is getting confused at POST.

 

[geofelt]

Your motherboard has two 8 pin aux cpu connectors.
They are needed for overclocking, high powered processors and to support extra graphics cards.
They both need to be connected.
Two 8 pin connections on a single cable may not work well.
Apevia is not regarded highly and 1000W and only two 6+2 pcie connectors for $89 should scream poor quality.

 

[Hallusion]

Did you plugin the power plusg to the 1st and 2nd gpu?

did you try each gpu seperated?

update the motherboard's bios

Yes

The PC won't start with the Tesla K80 connected to the PSU in any configuration I've tried. Including: K80 connected to power supply and PCIe 5.0 slot. K80 connected to power supply and PCIe 3.0 slot. K80 connected to power supply without being connected to the motherboard.

mobo BIOS is up to date

Can you confirm the K80 uses 1x8-pin PCIe power, not 12VHPWR?

it uses 1x8-pin. It's a 2014 card so 12VHPWR wouldn't have even existed.

Check your mobo BIOS and see if it allows you to install two GPU cards. You may need to define which is the primary (main) card for Windows(?) to use at boot up.

Can this be done with only 1 card connected? I can't make it to the BIOS with both connected.

Does your CPU have built in integrated video, adding a third GPU to the mix? No wonder the system is getting confused at POST.

I disabled the integrated video, but no change.

They both need to be connected.

they are

Two 8 pin connections on a single cable may not work well.

Is this referring to the cpu connectors or the gpu ones? for the GPUs, I'm using two cables, a single cable won't reach between the GPUs due to their different sizes.

 

[helpstar]

try the Tesla in a different system

 

[Hallusion]

try the Tesla in a different system

Tried another machine and it was able to power on.

 

[helpstar]

reset the cmos by jumper, while both cards are installed (power off from the wall before resetting)
try booting afterwards

 

[Hallusion]

reset the cmos by jumper, while both cards are installed (power off from the wall before resetting)
try booting afterwards

still doesn't boot

 

[helpstar]

did you try other power cables? even two 8pins of the same cable to try

try a different PSU if possible

take some pictures of your rig, upload to imgur.com or similar. maybe we can see something odd

 

[Hallusion]

did you try other power cables? even two 8pins of the same cable to try

try a different PSU if possible

take some pictures of your rig, upload to imgur.com or similar. maybe we can see something odd

I did try other cables.

I borrowed another PSU to test with but unfortunately it doesn't seem to fit my card, at least not with the cables it has. It has a PCIe cable like the one pictured here, but on the 2 section of the 6+2 side, instead of both connectors being rounded, only one of them is rounded and it doesn't fit the card.

Interestingly, when I connect just the 6 and try to turn it on, I get the same result as with the other PSU (RGB RAM lights up and nothing else). Dunno if that means anything.

(my original PSU isn't modular, so can't share cables)

 

[stonecarver]

my original PSU isn't modular, so can't share cables

Just an FYI Never use different power supply's cables. There not all wired the same. you can end up shorting PC out. 😱

 

[stonecarver]

instead of both connectors being rounded, only one of them is rounded and it doesn't fit the card.

Also are you sure your not mixing up mother boards 8 pin plug with the PCI-E 6+2 that's a big boo boo.

 

[Hallusion]

Also are you sure your not mixing up mother boards 8 pin plug with the PCI-E 6+2 that's a big boo boo.

I'm sure, it's the same cable that was plugged into the GPU of the machine I took it from. The mobo plug splits into 2 4-pins.

 

[stonecarver]

As long as your sure I just wanted to give you a heads up.

 

[Hallusion]

I was able to try my PSU in another machine with the K80 and I got the same result.

So that's:
2 machines/mobos with this PSU, neither of which boot with the K80
a 3rd machine with a different PSU that is able to boot with the K80

It's not definite proof, but the PSU is looking pretty suspect. I'm going to try replacing it tomorrow.

 

[helpstar]

the 2 pins of the 6+2 plug can slide in together before you plug it into the GPU