Unable to use RAM slots C1 et C2 on TRX40 Creator

Hello guys,

I recently purchased a TRX40 motherboard and I'm facing a problem with only RAM slots C1 and C2.

The RAM I have is 2 pairs of Corsair Vengeance LPX 32Go (2x16Go) DDR4 3200MHz (CMK32GX4M2B3200C16).

If I try to boot with only 1 stick on any on these both ports, the computer won't start (black screen).

Then, if I try with 4 sticks in either A1,B1,C1,D1 or A2, B2, C2, D2:
- I get the following error during the boot sequence: "Memory PMU Training error at Socket 0 Channel 4 DIMM 1"
- only 3 of the stick appears in the bios (A, B and D)
- CPU-Z indicates I'm in Triple Channel mode with a size of 48GB

I have tried all sticks on both of the C slots and get the exact same problem every time. Using any combination of 3 sticks also always works. I also tried to boot in dual channel with a spare pair of 8GB memory (CMK16GX4M2B3000C15). This tests make me think it is not due to a faulty memory.

I haven't changed any BIOS setting (factory default). I also checked the CPU pins and they all look fine.

Could anybody help me on this?

Looks like you are missing a channel there, most often this is because the CPU
isn't properly seated/mounted. It's particularly common with Threadripper.
Try reinstalling the CPU being sure it is properly seated and torqued down
(to spec). While you have the CPU out, check for bent pins in the socket.

If that fails then I would RMA that CPU.

Edited by Xaltar - 13 Feb 2020 at 12:32am

Based on past reports of similar issues on the forums here, I tend to suspect the
CPU first. In multiple past cases the culprit ended up being the CPU after all other
components had been returned/replaced. It is also one of the most expensive components
in the system so risking running over your return/RMA window while you wait on
other components may end up an issue.