Question Brand new build and mobo won't boot with 2 DIMMS in, will with 1 in slot A2

[Vanished]

I just built a newish PC a couple weeks ago and things have been fine but today I decided to upgrade the CPU to a Ryzen 7 9800X3d from the 7800X3D I had in it, I also swappedin a used 6800XT to replace the old 5800XT I was still using.

I am running an ASUS TUF Gaming x870 Plus-Wifi with GSkill Flare X5 DDR5 6000 CL28-36-36-96 and a Ryzen 7 9800X3D

After I got the new CPU installed and cooler mounted, I put the 6800XT in and tried to boot it up and I got the Yellow Led for a Ram issue.

So I swapped in some Corsair Vengeance DDR5 6000 I had and it gave me the Yellow Led also.

I had the two DIMMs in slots A2 and B2 as the manual recommends and I tried A1 and B1 and same thing.

So I finally tried one DIMM in A2 and I was able to get the system to boot up no issues.

Should I try reinstalling the mobo drivers and see if I can get 2 DIMMs to work or is there some setting I need to check in the BIOS or is the board gone bad and something is wrong with it running in Dual Channel memory?

I also swapped back to the 7800X3D thinking maybe the 9800X3D had an issue and it is doing it with the 7800X3D also.

Kind of stumped

Thanks for any ideas,

 

[Darkbreeze]

Pull the CPU and check for bent pins. Almost guarantee this is the problem. But even if it isn't, nothing you do means much if you don't rule that out first. So easy to bend pins on these modern sockets. Just look at it wrong, with some stink eye, and it will bend. LOL.

 

[Darkbreeze]

Check CLOSELY. Deviations are sometimes hard to see. Magnification will be helpful. Any variance at all, makes it likely. Especially since both AMD and Intel are now on very delicate LGA sockets.

 

[Vanished]

Pull the CPU and check for bent pins. Almost guarantee this is the problem. But even if it isn't, nothing you do means much if you don't rule that out first. So easy to bend pins on these modern sockets. Just look at it wrong, with some stink eye, and it will bend. LOL.

I pulled the board and it looks like there is a part that got bumped and maybe bent a couple pins. So I put in a brand new Gigabyte X870 Aorus board and was surgically gentle setting the Ryzen 7 9800X3D in to place.

Got it rebuilt using the new board.... SAME issue... it won't boot in Dual Channel (A2 and B2 slots) it will boot with one stick in slot A2.

I tried both the GSkill Flare X5 I have and the Corsair Vengeance, same thing.

I did however go and look at the Gigabyte site and these memory sticks are not listed on the QVL so I ordered new memory that is specifically listed as compatible and will try that.

I also have a new Ryzen 7 7800X3D here and swapped it in and still had the memory issue. If having "compatible" memory doesn't fix it I am at a complete loss.

 

[Darkbreeze]

Memory is VERY FRICKING picky when it comes to ALL Ryzen platforms/generations, no matter what the naysayers might say. It is. It, fricking, is. I've even taken memory from same generation Ryzen platform, installed it on a different board but with the SAME CPU, and won't work. So, it is VERY board dependent on top of being CPU particular.