Can't run 2 identical kits at XMP speed

Hi,

Hopefully someone is able to help me with this issue. I just build myself a X399 system with a Threadripper 1950X CPU and a X399 Taichi motherboard. I'm extremely satisfied but I've got a problem with my RAM.

I bought some quite expensive 2 x identical kits G.Skill F4-3200C14Q-32GFX - 3200Mhz, CL14, single rank, Samsung B-die. I though I would get at least these advertised speeds. Well, it turned out a bit differently. I can boot fine at XMP speeds only when just one kit (4 sticks) is installed. If both kits are installed I can't boot with anything higher than 2933 Mhz (8 sticks).

I used the following settings (at once) to try and boot with 2 kits (8 sticks) at 3200 Mhz:

1. Raized SOC voltage (vddcr_soc) to 1.2V
2. I left vddcr_soc_s5 on Auto as I was unsure what this is. On Auto it reads 0.9V and I can set it no higher than 1.2V
3. Changed SOC LLC to Level 2
4. Raized RAM voltage to 1.5V
5. Loosened the timings to CL16
6. Changed ProcODT to 60 Ohm
7. Changed Command Rate to 2T

And I still couldn't boot higher than 2933. I can hit 3600 Mhz, CL15, CR 1T fine with just one kit so I think they should be capable enough. By the way, my BIOS version is 1.5. Would flashing 1.7 (the newest one currently) help run both kits at XMP speed?

Thanks in advance!

Fair enough, thanks a lot for your input! I will remember to post here if I get better speeds on 8 dimms in the future.

p.s. im having some time this morning with my ram and its cold boot issue

so far fingers crossed ive made progress

i will update with my findings and see if i can help you get a little further