Monitor won't boot after adding 6th GPU

[Nelayme]

Hi all,

Newbie here. Straight to the point
GPU - 6x RX 6800 (4x250W TDP, 2x300W TDP)
PSU - 2x2000W
Mobo - Asus Z390 A
CPU - Intel Core I5-9400F
RAM - 8 GB

The problem I’m facing is that I can’t start to run my 6th GPU no matter what. I’ve swapped PCI-E slots, risers, cards - nothing. PC starts with 5 GPUs just as usual but whenever I add the 6th one - it powers up but I just can’t get a signal to my screen (can’t even get a bios screen as the monitor goes to sleep mode). Also, white and orange q-LEDs come as well what means there are some issues with VGA and a boot.

PSU 1 - is in charge of mobo, 3x gpus, cpu fan, sdd, molex cable to trigger 2nd psu
PSU 2 - is in charge of 3x gpus only.

Tbh, I was able to run all of them at the very beginning of this rig build but then some errors popped up one by one.
Some say it’s because of CPU that I have as F series can’t handle more than 5 gpus

Any clue what method could help me?

[mathelm]

Where is the monitor plugged in? If it’s plugged into the motherboard, try plugging into one of the gpus. If not my guess is that you’ve run out of pcie lanes on that motherboard.

Plus, many don’t even run a screen on the rig itself. Have you tried looking at your Hiveos page to see if the rig shows up? Maybe try it without a monitor plugged in.

Keep in mind I’ve only been at this myself for a couple of months, so take everything I say with a grain of salt.

[Nelayme]

Monitor is plugged into one of the gpus at all times . Forgot to tell you all I run on TRM but obviously it’s not an issue as I can’t get a bios screen whatsoever. Just been thinking if motherboard provides enough of power to start pci-e slots.
One more thing what I’ve noticed, say, I make changes on bios menu, whenever I exit pc TRIES to run the system but it restarts itself twice till it manages to run normally. It’s like trying to start a car with a low battery or something

[felcruel]

I have the same problem as you, but with gigabyte h61m-ds2h and i3-2130. And it also happens with the 6th gpu. Tried to disable onboard gpu and it didn’t work. Made my peace with it that its probably mobo limitation.

There are some topics to configure the bios (enable 4g encoding, gen2, etc), try that and see if it works

[asusetyo]

I use H61M-P20 (G3) and having the same issue for the 6th GPU having blank screen without signal, my PSU is more than enough to cover up to 8 GPU. Tried to take turns on GPUs, just to make sure it is not GPU issues, but as long as it is only 5 GPUs it runs well.