Question QCode 0d with specific RAM-Slot usages - no Post

vffa

Honorable
Jun 28, 2016
3
0
10,510
Hi there,

I have a very odd problem with my new Build. Lemme give you the specs first.

CPU: Ryzen 5900X (NEW)
RAM: 2 x 2 x 8GB Vengeance LPX 3600Mhz (CMK16GX4M2B3600C18) (Samsung Dies)
MB: Asus Crosshair 8 Dark Hero Wifi (NEW)
GPU: XFX 7900XTX with Waterblock (fairly new)
PSU: BeQuiet Straight Power 10 800W
Cooler: Custom Loop with an EKWB Quantum Velocity Waterblock for the CPU.

So, i just did a full upgrade from my 6700K+Vega64. They served me good, but as I got a new monitor they just couldn't keep up anymore. I already owned the RAM and it worked fairly well so far.

Yesterday i finally got time to assemble the new Build and after everything was set up (loop takes time) i went ahead and started the PC. However i only got the DRAM light and Qcode 0d (reserved for future EMI whatever). This would point to the RAM, the board or the CPU memory controller.
I tried it with only 1 Dimm inserted at a time, going through all slots, didn't post, same Qcode. Damn.

I then updated the BIOS, cleared CMOS, replaced the CMOS Battery, tried CPU, 1 Dimm and GPU only, still nothing. Damn!
Tried without any RAM, same 0d Qcode. Hm. Maybe it's not detecting the RAM.
So i reseated the CPU, made sure the Pins were all fine (twice) and reinstalled. Now I could get into the BIOS but only with 1 specific stick in the B1 Slot. No other stick worked, and the working stick (I'll name it No. 27 here as these are the last 2 digits of the serial number) only worked in B1.

Okay, so something is definitely wrong here. I reinserted number 27 into the B1 slots again and I get the 0d again. Now I'm a bit confused. I thought maybe it's the CPU mounting pressure, as AM4 seems to be a bit sensitive in that regard.

So, i loosened all the Screws on the waterblock and retried, slightly increasing the mounting pressure after each failed attempt. Didn't work. I tried the other sticks, didn't work either.
So, i went back and reseated the CPU once again, made sure there are no bent or broken pins again, and check the socket for anything that would be suspicious. Nothing.
I now only screwed the waterblock on with literally zero pressure on the CPU (just so it was in place). And I went ahead and installed No. 27 into A2. I'm getting into Bios.
Nice! Installed No. 26 into A1. Qcode 0d again. Damn. Put No. 26 into B1. Get into Bios. Nice!
Tried putting No. 84 into A1, get Qcode 0d again. Tried it in B2, Qcode 0d.

I swapped No 27 and No 26 for No 84 and No 85, and it works.
So, the RAM works, as expected. But only in slots B1 and A2.
The question now is, is the CPU defective or the Mainboard. Or is there just problem with the mounting pressure? I should mention that I have already tried every possible tiniest change in mounting pressure i could make. But nothing really changed.

I unfortunately don't have a second AM4 CPU or MB i could try.
Any one has any ideas on who's the culprit here?

If you have any further questions, don't hesitate to ask, I'm grateful for any help.

I should note, that this is far from my first Build and I'm usually pretty goodwith troubleshooting, however this leaves me puzzled as i can't really pinpoint who the culprit might be.
 

Lutfij

Titan
Moderator
RAM: 2 x 2 x 8GB Vengeance LPX 3600Mhz (CMK16GX4M2B3600C18)
Can you check and see what the PCB versions for both ram kits(and maybe each stick of ram) are...?

For the sake of relevance, can you state what BIOS version you're on at this moment of time for your motherboard?

I unfortunately don't have a second AM4 CPU or MB i could try.
I would advise on dropping your processor and ram kit onto a friend or neighbor's (AM4)motherboard with the right BIOS version(and ofc VRM cooling) to see if your processor's IMC might've conked out.

Out of curiosity, while breadboarded, did you experience any issues(before you setup the entire build and plumbed the loop for your watercooling build?