Question Non-working ram slot moves on MB

[Dubya USMC]

During my new build I installed a single ram chip to prevent any issues during updates and installations. Then after updating UEFI, installing Windows, and updating all drivers and software, I went to install the remaining 7 ram chips in sequential order and came across what I though was a dead slot on the MB (4F q code- pch memory initialization)... So I began standard troubleshooting with pop-swapping chips to ensure it wasn't a dead chip and confirmed it was the D1 slot. I then pulled the CPU to inspect the pins and reseat it. Afterwards started over on the sequential testing of slots and chips and came across the B2 slot and found it was dead BUT the D1 is now working. I've done this 3 other times and each time a different slot is dead and the others would be working... So any clues what may be causing this cuz my head is hurting from scratching it so much. I'm hoping it's not the MB and just the CPU or a setting I can change.
Build:
Threadripper 2990WX
Asus X399 Rog Strix E-Gaming (0808 bios)
8x16GB Corsair Vengeance Pro 3200
2x Gigabyte 2080 Ti Extreme 11GB
M.2 Samsung Evo 870
Windows 10 Pro completely updated 3-24-19
Ekwb Custom Loop

 

[Calvin7]

Run MemTest86. If you get any errors, return the entire kit to be replaced under warranty.

3200MHz memory
You don't mention what you have it running at.

Supported memory configurations:
https://en.wikichip.org/wiki/amd/ryzen_threadripper/2990wx

 

[Dubya USMC]

Run MemTest86. If you get any errors, return the entire kit to be replaced under warranty.

3200MHz memory
You don't mention what you have it running at.

Supported memory configurations:
https://en.wikichip.org/wiki/amd/ryzen_threadripper/2990wx

I have it at 2133Mhz for an 8 stack I'll run the memtest and see what it comes back as when I get back from work.

 

[Darkbreeze]

My guess would be that you have one bad stick, and moving it to a different slot has made it SEEM as though the bad slot is moving. If you can identify a slot that's not working, and swap that stick with another stick, and the problem remains on that slot, then that would disprove that theory, but if it moves then you know which stick is bad. If you have to RMA a bad stick, you make SURE that they RMA the WHOLE kit. Replacing one stick on a set that is supposed to be matched and tested, ESPECIALLY on these 8 stick kits where there is a lot more room for discrepancies between sticks when running at XMP speeds and timings, is unacceptable.

We buy kits for a reason. When we buy a kit we expect it to all work and when it doesn't, the whole kit should be replaced regardless of how many DIMMs are in the kit. We've seen a number of people here who've had the manufacturer replace only one stick, which didn't play nice with the rest of the kit, and had to end up insisting on the replacement of the whole kit which of course in practically every case solved the issue.

Of course, there's always a chance there's an issue with the motherboard, but I'd definitely try to determine first if the problem is moving because one of the sticks is moving.