CPU or Motherboard toast?


Jul 31, 2009
My main computer (3930k in sig) this evening had a hard crash while I was watching a video and updating my Win 10 virtual machine. Upon rebooting, it blue screened during startup about 30 seconds after the "Starting Windows" screen comes up, with an error 124 code, quickly reboots, rinses, and repeats. The same will occur (though sometimes a 9c code instead) if I run the startup repair option, and that will actually get to the repair window first. I know 124 is a hardware failure code, the problem is, which hardware?

Some history: I have been running with only 3 DIMMs working for awhile now (though 4 are plugged in and recognized by CPUz all the time, and some of the time by the BIOS, but not Windows or Memtest), and all 4 sticks are confirmed fully functional in another computer. Temps are very nicely placed, at full bore with DC (which until I started my VM today was almost 3 solid weeks of crunching on 6 cores), I run at maybe 36c with ambient 10c. I save on heating.

So far in my attempts to find the culprit I've stripped it down to the following (going to stock from OC was #1):
CPU, MB, 1 DIMM, SSD, GT430 or GTX580 GPU
No change to the bluescreen loop.
On my way down to that configuration, I first pulled the dimm from the non-working channel the dimm LED stayed on and the MB looped without posting. Pulled another channel out and it posted fine. If you're curious, channels A and C are the only ones working.
I reseated the CPU and checked to make sure the thermal grease hadn't leaked off the top (it hasn't), still no go.

The CPU and board are still under warranty, and I'm 90% sure it's the motherboard. I don't have a spare CPU or MB in this socket to test with, and considering the cost of buying a "cheap" testing replacement and my current lack of finances, it is basically out of the question. Is there anything else I should try? Anyone have a similar situation and solution they can relate? Which piece do I RMA? Help! (and hanks in advance :))