4xDIMM DOCP + 2xGPU won't POST

[Gergo]

I have 2 kit of F4-3200C16D-32GTZR, which took me a lot of slot switching to make it work with DOCP on 3200MHz with 1 GPU.

Now I had a great idea that I needed 6 monitors, therefore I needed an extra GPU, so I have a 2070Super and a 3080Ti, and it took me hours of debugging why the system wouldn't post with 2 GPU, and the problem was with the DOCP. As soon as I let the RAMs run on JEDEC defaults, the problem goes away. 

 

I've tried 1.4V on RAM and 1.1on SoC, switching slots to all possible variation, no luck. The system runs on Asus x570 TUF PLUS mobo, could that be an issue ? I've read the manual that it doesn't support 2xGPUs, because it won't split the PCIe lanes to 8x/8x, but it would split to 8x/4x, which doesn't cause any performance loss due to PCIe 4.0. Also it wont boot if the 3080Ti is on the top slot, only with the 2070Super on the top (regardless of RAM settings).

Do you think an upgrade to the Crosshair VIII Dark Hero which supports PCIe 8x/8x would solve the issue, or is it unrelated, and I'm just unlucky ? Is there any debug steps I could take to help me solve my problem ?

 

Thanks.

[Moonzy]

11 minutes ago, Gergo said:

I've read the manual that it doesn't support 2xGPUs, because it won't split the PCIe lanes to 8x/8x, but it would split to 8x/4x

you... what?

it doesnt support SLI, which doesnt have anything to do with multi GPU

i plugged in 4 GPU into a x570 TUF (with risers)

 

12 minutes ago, Gergo said:

Is there any debug steps I could take to help me solve my problem ?

turn your RAM frequency down to 3000MHz, and try

if it doesnt work, turn it down even more

[Gergo]

14 minutes ago, Moonzy said:

you... what?

it doesnt support SLI, which doesnt have anything to do with multi GPU

i plugged in 4 GPU into a x570 TUF (with risers)

That's great, I don't need SLI anyway.

14 minutes ago, Moonzy said:

 

turn your RAM frequency down to 3000MHz, and try

if it doesnt work, turn it down even more

yeah I tried 3000MHz, then it wouldn't event go to automatic failsafe mode, just hanged so I had to clear the CMOS. I'll try lower tomorrow.