XPS 8950, DIMM1 won't recognize Crucial 32GB DDR5

That blink code shown here, indicates a BIOS ROM failure which makes sense. You could try pulling the CMOS battery for 15 minutes or so then reinstalling. If that does not help then a call to Dell tech support may be in order. The fact that the DIMM slot does not detect the 32 GB RAM could be a MB fault. But also very possibly a BIOS error as the blink code indicates.

As for which slots match the colours, both white then both gray.

Thanks JOcen,

Pulled the power and the CMOS battery (for at least 15 min).  No luck, it still does not like the 32GB stick in slot 1.  By the way, I was wrong with the code in my first post, the code is 2,4 and per the service manual that's "Memory or Random-Access Memory (RAM) failure".  Since these are two brand new sticks and the result is the same with either in slot1, however the system recognizes and boots with the RAM in the other slots, I am leaning toward a MB issue.  It can happen I guess

I already have a case open with Customer Care, I was upset the box arrived with a good size ding and scraped paint on the top of the case, no damage to the shipping box however.  The internal wiring was also all over the place and found a 4pin power plug stuck in the CPU fan (shaking head).  I re-ran all the wires and cleaned it up.  If I didn't have the RAM issue I would just keep, but I think I will take them up on sending me a replacement system at this point.

I have to agree that the MB sounds like it has a problem. No problem with the blink code mistake, your 2 - 4 sounds more logical. And no reason to keep it with the dings and wiring haphazardly located. Once this gets sorted out , if you could update the post as we all like to see the end result.

Will update for sure.  I already had some nice parts laying around, pair of 2TB NVME drives and the 64GB of RAM.  So it was ordered with the min SSD and Mem. I was going to look into a better CPU Cooler but that will be later after I get the RAM issue sorted out.  Once I got the wires re-organized it looks really good inside.  Here is a after cleanup photo for reference.  Its hard to find an 8950 non AIO photo.  The non-k CPU cooler really needs to be upgraded if you ask me.

@dstewart51  No offense intended, but how are you numbering DIMM slots, by the numbers printed on the motherboard or...?

You should put your new matched pair in 2nd and 4th slots, counting from the CPU. The one closest to the CPU is DIMM3. So counting from CPU: DIMM3>DIMM1>DIMM4>DIMM2.

@RoHeNo offense taken, its a reasonable question.  I listed the slots as numbered by the MB, DIMM1 and 2 being white, 3 and 4 black.  As shipped, there was a single 8GB stick in DIMM1, this is the slot that wont recognize the Crucial 32GB stick (CT32G48C40U5), all other slots do.  Here is a photo  I took during my first attempt with the 32GB sticks in DIMM1 and DIMM2 (white slots).

@dstewart51  OK, just trying to cover all the bases...

Did you order this PC directly from Dell on line or from somewhere else?  Could it have come from Dell's outlet store?

Sounds odd that it's scratched and the wiring was in a mess. You might want to ask them to replace the entire PC with a new (not refurbished) system, instead of just the motherboard...

Post back and let us know what happens...

Directly from Dell, brand new, custom configuration.  I suspect I just got unlucky with whom ever assembled it.  Dell already offered to replace the entire box with a new, exact build.  I'm going to take them up on the offer.  The dent and scratch I wasn't happy about but could get over and live with, I was disappointed about the wiring but I corrected. They say about 8 days for a replacement.

I spent some time on the phone with Dell Tech Support to double check this ram and configuration is supported.  The RAM is supported, two sticks are supported, but NOT IN SLOT 1.  They are telling me, DIMM1 one can only accept 8 or 16GB sticks at 4400MHz and I should use DIMM3 and 4  for both of the 32GB sticks.   Something is not adding up in my mind.  The MB is spec'd at 128GB, 4x 32GB albeit at 3600MHz, but my 4800MHz should work at the lower frequency and the MB should auto select the max capable speed.  They dont layout the specific memory configuration per slot in the available manuals, only it should work.  I would sure like to hear if anyone else has tried 2x 32GB sticks in their 8950.

Okay, now I'm upset (because I cant use the word that starts with P).  Just got my replacement PC from Dell.  As I was removing the PC from the box I heard a loud bang and rattle in the CPU case.  I pulled the cover and found it just like this, I KID YOU NOT!   Literally, I am speechless at this point.

Edit, not only was the CPU heatsink not mounted, it banged around during shipping and knocked off the heatsiknk from what I think is the Z690 chipset.  That heatsink and the retaining wire is down by the power supply.  Of course I just tried to contact Dell, and all I get is  "That Department is closed right now, please call back".

There's no telling how far and how many times that box got dropped, kicked, and thrown around during shipment....

Hope you cleaned both surfaces and installed a thin layer of fresh thermal paste before you remounted the CPU heat sink. If not, you should do that before using this PC again...

You should contact Dell on Monday and explain the issues. Ask them to send a support tech to check out and remount those components, if you want one to come out. At the least, get on record about what happened.

I put the heatsinks on, and it booted.  So I thought I would test the Crucial 32GB sticks at least.  Starting with one 32GB stick in DIMM1, this worked.  Next, added a second stick to DIMM2 (both white slots), this worked as well.  So this seems to confirm the MB in my first shipped box is bad.  A bit leery of keeping this one since the CPU heatsink was banging around inside.  But at least this confirms you can run 64GB RAM (2x 32GB) in DIMM slotts 1 and 2.

I also now think the Z690 heatsink simply was not mounted, I cant see how it could be knocked off with the way the wire mounts it.  It appears whomever was responsible to mount the Z690 and the CPU heatsink just didnt.

@RoHeYes, Ill be calling for sure.  So far the new box seems to be working, running it through the tests, running Windows Memory Diagnostic to be sure.  Runs better than the first box for sure.

Yeah, I ditched the Thermal Interface Compound on the Z690 and removed some tape on the bottom of the Z690 heatsink, then remounted with Arctic MX5.  That little heatsink gets warm for sure.

Did the same for the CPU heatsink.

@dstewart51  - Well done!