Question Bios/windows doesn't see ram in slots B_1 and B_2 (memory PMU training error on post)

EpigGforce

Distinguished
Nov 29, 2011
17
0
18,510
0
This is a new build, AMD 3700x, Gigabyte Aorus Elite X570 mobo, Gskill Ripjaws V 8gb 3200 ram x2.

When I first built this PC I could not get it to post at all. No beep from my mobo speaker, all the lights would go on besides the orange one on the mobo, and no post screen. So I RMA'd the mobo.

Got it back, and it posts. However BIOS does not see my ram in slots B_1 or B_2, and I get a Memory Training Error. Windows only sees 8gb of ram too.

As long as I have ram in slots A_1 and/or A_2 I get a post screen. (so I can run them both in single channel) If I just have sticks in B_1 and/or B_2, it doesnt post. This leads me to believe that it is not a ram problem, but a mobo/cpu problem.

Ram only runs at 2133. If I try to run XMP profile 1 it fails to post (bios resets).

Another thing that is weird is that CPU-Z sees the memory in slots B_1 and B_2 if it is in there. Something is still messing up in the memory tab, as the Channel # is not filled out and DC mode is completely greyed out when running in A_2 and B_2. (although for size it shows 16gb)

This would make me think that it might be some CPU error, but all the pins are straight and clean, and it sits well in the socket.

I've flashed to the latest bios version (F11), reset cmos, reseated the CPU multiple times, to no avail.

Obviously something is still wrong with the motherboard, or wrong with the memory controller on the CPU. Is there any way to tell which one is the problem? Is there any other troubleshooting I should do?

I appreciate the help, this build has been a nightmare so far.
 

Nemesia

Commendable
Nov 6, 2019
1,368
237
1,290
56
Let's start with your motherboard manual.

When you have 2 sticks of RAM you have to put your RAM in the A2 and B2 slot. That's how you get your Dual Channel. The manual specify A2 and B2 when you use 2 sticks to be used first. A1 and B1 can be used too.

Now. Your RAM. " Gskill Ripjaws V 8gb 3200 ram x2. "

Is that 2 sticks bought individually or were they coming in sealed packaged kit?

If that's 2 sticks not from a kit that could be your issue. Mixing ram not from a kit even if the RAM are from the same brand and model does not guarantee that they will work fine together.

A2-B2 with XMP off should be tested first.
 

EpigGforce

Distinguished
Nov 29, 2011
17
0
18,510
0
Yes, ram was an identical pair in a sealed kit. It will post with either stick in A_2 and B_2, (as well as A_1 and B_1) with XMP off, but BIOS/Windows does not see a stick in B_2 (or B_1 if it is in there), although CPU-Z does see ram in B_2 (or B_1)
 
Last edited:

EpigGforce

Distinguished
Nov 29, 2011
17
0
18,510
0
Quick update:

Ran memtest86 just as a sanity check, no errors but also only sees 8gb of ram (probably also goes through the memory controller on the CPU).

Also tried downgrading my bios from F11 to F4, and interestingly enough the computer would not post. Not sure if the ram is not supported in that rev, I didn't do any troubleshooting in F4.

I'm wondering if there could possibly be any thermal paste in one of the pin sockets on the motherboard? It looks clean and the pins on the cpu are also clean, but I think it might be worth a shot. Right now it looks like my next step is to RMA the cpu.
 
If the CPU and its socket are free from any dust, dirt, paste etc, and there is no apparent damage to the pins and pads (including bent pins), then remount the CPU carefully and evenly. Uneven mounting can cause loss of contact for some pins/pads with consequent memory issues occurring.
 

EpigGforce

Distinguished
Nov 29, 2011
17
0
18,510
0
I sent the CPU to AMD for an RMA, they accepted and sent me a new CPU. Problem has not changed. I'm a bit SOL cause of whats going on in the world right now. I'm thinking of just buying a new mobo at this point.

Is there any chance it could be the RAM? As I've said, they swap fine and I can run them in single channel in A_1 and A_2 but not in B_1 and B_2, and when running in A_2 and B_2 or A_1 and B_1 I only see 1 stick in either A slot.
 
As each individual memory module works, it is unlikely to be a memory module issue.

Despite replacing the CPU (and presumably it is mounted evenly, and presumably there are no bent or damaged pins?), it seems the ongoing issue with unavailable memory slots (B channel) is now most likely due to a faulty motherboard.
 

ASK THE COMMUNITY

TRENDING THREADS