Build can boot ONLY after a CMOS Clear

Joined
May 14, 2025
Messages
3
Hello,

The issue:
My computer can only POST right after performing a CMOS Clear. After it manages to POST, if I:
- enter BIOS and exit, or
- boot Windows and shutdown, or
- boot Windows and restart,
then it can never POST again until I perform a CMOS Clear again.

The build:
Motherboard: MSI MAG MORTAR B850M WIFI
Current BIOS version: E7E61AMSI.1A30 (April 18, 2025)
CPU: 9950x
RAM: CMK96GX5M2B6400C32 ver5.53.13 (It's a 2x48GB kit with SPD 4800MHz/1.1V and it's on the MB's QVL)
PSU: Corsair SF1000
SSD: Crucial T700 Pro

What happens after a CMOS Clear:
I perform the CMOS Clear by pressing the corresponding button at the rear of the motherboard.
When I start after a CMOS Clear, the CPU (red) and DRAM (yellow) leds stay on for ~50 seconds, then they go off for a few seconds, then the DRAM (yellow) led stays on for a bit less than 2 minutes. After that, I see a screen telling me hardware changes were detected, and asking me whether I want to enter BIOS or continue with default settings.

If I choose to continue with default settings, I'm able to boot into Windows correctly.

If I restart the PC from Windows, or I choose to enter BIOS and exit it (with or without any change), then the DRAM (yellow) led stays on indefinitely (I tried letting it for up to 2 hours).

From there I can shutdown the PC by holding the power button for 5 seconds, but when I start it again, the CPU and DRAM leds stay on indefinitely. Same thing if I shutdown the PC from Windows after I manage to boot, and start the PC again.

What I tried so far:
- using the two sticks in A2 and B2, or a single stick in A2 changes nothing.
- entering the BIOS and tried changing the following settings (only one change per attempt) changes nothing: changed Memory Context Restore from Auto (default) to Disabled, changed PBO from Auto (default) to disabled.

Other information:
- the CPU, RAM, PSU and SSD worked fine on an ASRock B850M Pro RS. I wanted to try the MSI MAG MORTAR B850M because I had stability issues with my RAM kit with anything above 4800Mt/s, and hoped to get better results on the MSI one as this kit is on its QVL.
- in the MSI BIOS (with default settings), it says the Core Voltage is 1.354V. I find it strange, I was under the impression that it was a rather high value for Ryzen 9000.

My options are:
- try another RAM kit on the QVL,
- try another PSU, as I saw in this thread that another person seemed to have similar issues with a Corsair PSU,
- send back the MSI motherboard, keep the ASRock one, and try another RAM kit on it.

What are your thoughts?
Thanks for your help :-)
 
Please clean the memory module's golden finger with eraser and switch the memory module connected sequence to check whether the symptom could be improved.
 
More tests done, new results.

My sticks are labelled #1 and #2 by the manufacturer. So far I only tested with #1 in A2 + #2 in B2, or #1 in A2 only. I tried #2 in A2 only and all the issues are gone: memory training is faster, and now stable: I restart, sleep, shutdown, go into BIOS without issues.

After this, I tried adding #1 in B2, and the issue came back immediately. Therefore, I suspect my #1 stick is defective, and the other components of my system are probably fine.

As @zerijelly mentioned, I'll try cleaning up stick #1 and redo the tests.
 
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