I'm building a pc and upon startup, all components turn on but then the debug LED on my Extreme4 motherboard shows codes 14, 15, and finally ends on and remains at C5. There is no output to my display which is connected to the GPU. The manual only tells me that code 15 is PEI_CAR_NB_INIT (which I don't really understand), but codes 14 and C5 are entirely unknown. I've played around with my RAM and my storage, and found that with ram uninstalled, I then remain on error code 10. If my storage is uninstalled, I get the same 14, 15, C5 sequence of codes, so I assume that my storage is not being read at all. I plan to return my storage and get one that is compatible as per this sheet. My storage is WDS500G2B0C, which is just 1 serial number away from the one listed there.

However, I also notice that my ram is not explicitly stated on the memory QVL sheet, so I'm not certain that this will not also cause problems after I install the new storage. If anyone has any idea what those 14, 15, and C5 error codes mean, I would greatly appreciate if you could share. My bios is on 1.00, which is what it shipped with. I think there is a later version available, but I can't even get into POST to try and update it. The full mobo manual is available here, and my parts list is here.

CPU 9950x

GPU 5090 Astral

MOBO X870E Nova

RAM Corsair Titanium 6600Mhz 2x48GB

Just built my workstation and couldn’t get it to post.

Tomorrow should try to reseat the sticks. If doesn’t work then try both of the sticks separately in A2.

Before installing CPU pins were fine, even made a post on Reddit since I was worried and it was said that everything is how it’s supposed to be.

Installed CPU carefully.

How deep am I? I didn’t wait for Noctua Edition TX1600 since it would’ve been 3 months when I would’ve gotten it and replaced it with ASUS ROG STRIX PLATINUM 1200W.

Need this workstation to be up and running tomorrow, I need to render 3D animations asap.

Just finished building my new build and went to boot it… DRAM light on, C5 error code -> 15 ~30 seconds later. Initially, I was using 2 memory sticks and then tried 1 memory stick, with no luck at all.

I am pretty confident that the CPU/MB pins were not bent during installation.

I was reading other subreddits, and some people found flashing bios to fix it. I'm going to give that a try tomorrow, but I was curious what more people thought.

Also any other suggestions for how to test, let me know; I’m building my brother a pc as well, and can technically test with his parts. Really hoping I don’t have to resort to that.

Update: Started reading the manual and found that 15 means " Pre-memory North-Bridge initialization is started." but nothing for C5? . Tried just leaving it for 10 minutes and nada.
https://www.gigabyte.com/Motherboard/X870E-AORUS-ELITE-WIFI7/support#support-manual

Build: CPU: 9800x3d (s/o microcenter)
MB: GIGABYTE X870E AORUS ELITE WF7 AM5
Ram: CORSAIR DOMINATOR TITANIUM 64GB (2x32GB) DDR5 6000MHz CL30 AMD Expo
GPU: 4080 super TUF
AIO COOLER: Lian Li 360mm

Just spent 8 hours building and got an error code C5 on the motherboard. The PC then power cycles. Anyone ever have a similar issue? There is not much to find when trying to search for it.

Specs are below:

PCPartPicker Part List