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R4E: Won't boot after unexpected BSOD 124 (after 3 years of flawless function)

WillyK
Level 10
Hi guys.

My custom built rig has served me flawlessly the past 3 years. The other day I experienced a sudden BSOD code 124 while rendering a video, and now it won't boot.

The post stops after initializing the HDDs and the screen remains black while nothing more happens. The Q-code on the board shows "b2" and the "boot device" LED remains lit. No indications of a memory failure. I've switched to the second BIOS (with default Asus cfg), replaced the video card, but it didn't make any difference.
Given that the rig was working fine just before the crash, I wonder what could have failed. I suppose it could be the CPU but I kind of doubt it. It never complained or caused any troubles prior to this. Disassembling the rig to get to the CPU (e.g. to try reseating it) is a huge project, and I'm not sure it's worthwhile the effort.

I'm not exactly a novice and I always have been able to get around such problems before, but now I feel a little stuck. I'd like to avoid stripping down the build and starting from scratch (it will be like building it up again), and I'd like to try a few things before doing that. My "intuition" is telling me that it's probably something "stupid" getting in the way of the booting, especially giving its flawless function until this crash, but I just can't figure out what this "something" is.

I'd greatly appreciate a good advice. Thanks!

All details about my rig are included in the enclosed image.

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16 REPLIES 16

Arne_Saknussemm
Level 40
Hi WillyK

0x124 is typical memory BSOD and B2 on that platform often pointed to memory training failure...

Have you done the basics, like clear CMOS with power removed from the board.

Try one stick of RAM in the recommended slot...that sort of thing.

Is the boot device OK? have you tried disconnecting the drive with the OS...maybe try it in another PC if you have one?

WillyK
Level 10
Hi Arne and thanks for your lightning response!

Yes, I've tried clearing the CMOS, the boot device is OK and I also tried disconnecting it (and other HDDs too)... no difference.

I'm pretty sure it's not failed memory, but you may be right that the "memory training" gets confused. That's why I recently asked in another post how to get to the BIOS right away... The problem with playing around with the RAM is that it's water cooled and disassembling the RAM cooling is a nightmare. Of course, I may have to do it at the end of the day but...

SInce the crash occurred on video rendering, I first thought that the video card failed (CUDA etc.) but ... it wasn't that.

Anything else I could try before massacring the rig? If I could only get to the BIOS to turn off the RAM training etc...

Arne_Saknussemm
Level 40
You can´t get into BIOS by pressing delete key repeatedly? Or have you not tried that?

When you switched to second BIOS could you not get into BIOS?

Have you tried flashing the BIOS BIOS flashback method?

What BIOS and what CPU are you on?

If you had a RAID setup and you cleared CMOS you´d have to go into BIOS to set controller to RAID again...that sort of thing..

WillyK
Level 10
No, unfortunately. The process doesn't seem to reach the point responding to my Del/F2 hits. Switching the BIOS did not make any difference, so it's just the same behavior. I haven't tried flashing the BIOS but since two different BIOS installations behave the same I thought that it won't make a difference. The second BIOS is Asus default (no OC).

The rig has been running super stable on BIOS 4901. The CPU is i7-4960x and it wasn't pushed too much.

I don't use any built-in RAIDs. My Areca RAID is using its own (PCIe) controller and initializes just fine. I have other drives initializing after this RAID during post so it's not the RAID stopping the post. I think the post stops just before showing the summary screen before entering the OS. I'm not sure what the post is doing between initializing the HDDs and this point, but it may be the "memory training" and such. I wish there was a documentation of the sequence of operations post is performing (with corresponding Q-codes when relevant) just to see where the process possibly stops... I've tried to find such information but ... in vain.

Arne_Saknussemm
Level 40
Well, it sounds like you will have to start pulling it appart...in the end the only way to isolate the cause is substituting and swapping pieces...:(

WillyK
Level 10
It surely looks that way... unfortunately. I've tried what I could think of clever ideas, and I was hoping that there may be other tricks (you never know all of them). Again, what puzzles me is that this should happen to a fully functioning rig all of a sudden and without any clues of what happened. Eh well, we all need some excitement in our lives 🙂

Arne, many thanks for your time and effort, and your moral support 🙂 Much appreciated!

Arne_Saknussemm
Level 40
Nah you´re welcome...sad it´s not an easy fix.

Sometimes these things happen...I had a PCIe controller die on me once...new CPU went x16x16 to x16x8 and then x8x8 and then dead within a couple of days

And once had a dead ram module...just takes some faff swapping things in a nd out to find what´s gone wrong...

Good luck with the troubleshooting!

WillyK
Level 10
I just wonder... Since I cannot get into the BIOS at all, is it fair to assume that the MoBo is causing the problem?
I mean, if it was anything else, even the CPU, then I still should be able to enter the BIOS. Or am I wrong?

WillyK wrote:
I just wonder... Since I cannot get into the BIOS at all, is it fair to assume that the MoBo is causing the problem?
I mean, if it was anything else, even the CPU, then I still should be able to enter the BIOS. Or am I wrong?


A working CPU is required to complete POST. Reseat the CPU, VGA and memory first of all.
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090