Threadripper 7970x W/ ASUS WS TRX50-SAGE & 3 X 3090's failing to boot

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1

Greetings,
For an AI project,
I have built a Desktop With the following Specs:

SPECS

CPU: Threadripper 7970x
Motherboard: ASUS Pro WS TRX50-SAGE WIFI
Memory: 4 * 64GB DDR5 @ 6000 (256GB)
SSD: 2 * 4TB NVME Crucial T705
PSU: Corsair AX1600i
GPU: 3 Nvidia 3090’s (2 Slot Designed Cards)

My Issue

This build boots fine with 1, or 2 GPU’s Installed, However, does NOT boot with 3 GPUS installed.
Moreover, It only boots with 2 GPU’s instilled when I use PCIE Slots 1 & 3 (From the top).
If I try using PCIe slots 1 & 2 for 2 GPUS, it also does NOT boot.

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More Details

To clarify, When I say Does not boot, There are no Error LED’s on the motherboard indicating an issue.
The LED Number typically is 36 or 37 (which both numbers show during bootup Whilst it is working as well so I cannot determine much from that).
And all fans and etc. are running, just no POST.

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My Initial Thoughts

My original thoughts is that perhaps 3 * 3090’s + system is too much of a load on the PSU causing it to not boot properly. The problem with that assumption is that from my experience, when a PSU cannot handle the amount of watts required for a build, it simply will not turn on at all.
Secondly, these 3090’s supposedly consume 350Watts each, and the CPU + system pulls around 400 watts,
So
350W
350W
350W
400W

1450W < 1600W

Secondly, When I see that using PCI slots one and two with 2 gpu’s also Does Not Work, It gives mee reason to believe that for some reason, this motherboard is not capable of having GPU’s Installed in Pcie slots 1 & 2 regardless if there is a 3rd gpu in slot 3 or not.

Does anyone have any information as to why this motherboard does not allow this configuration or if anyone else has had success with a 7970x & 3 GPU’s

Much Appreciated!

1 Like
2

Have you looked at the motherboard manual? It will tell you exactly what your problem is.

IIRC, after it finishes it’s initialization, it will show CPU temp, usually, so you might be booting fine, since 36-37c is not an unrealistic temp. at idle

When a GPU is listed at a certain amount of power, it means that’s the maximum it can pull. GPUs normally idle at 5-30w, so boot failure due to power supply capacity is not a concern here.

2 Likes
3

If i would use 3 GPU i would buy WRX90. 6x PCIExp 16 5.0 slots and 144 usable PCIe 5.0/4.0 lanes.

4

Getting exactly the same issue here.
We are actually trying to install 4 x 3090 GPUs, but, when installing the third, the mobo struggle to start.
Maybe someone already have found the solution? :pray: