RAM suddenly is not detected.

[alue2236]

Hello,

I have a z790-i strix motherboard with G.Skill Trident Z5 RGB 32 Go (2 x 16 Go) DDR5 6400 MHz CL32 and a 12900kf. Everything was working just fine for couple of months until one day the motherboard just stopped detecting the ram modules. The debug LED just keeps showing the constant orange light. I checked everything. I used another psu, I used another cpu, I tested 1 stick at a time, I upgraded to the newest bios, but still it didn't work. Then I used another stick of ram from another pc and it booted. So I told myself, that maybe the RAM is the problem, but how is it possible that 2 sticks of RAM suddenly stop working? I then tested the ram in another pc and it booted without any issue. At this point I have no idea what could be the problem, but if there is someone who could know something, please let me know.

[JohnAb]

Frustrating. Hard to know what the problem is, but probably not the RAM or the motherboard in this case as it works under some circumstances. I'm thinking that remounting the CPU might be worth a try. If there is the tiniest speck of dirt or dust, a damaged pin or maybe even if the CPU cooler is too tight or not evenly tight, then all sorts of strange problems can show up. 

I understand that it was working before and that your RAM swapping results make no sense, but if any of the CPU contacts are unreliable for whatever reason, then it could be that. 

Have you tried setting the BIOS back to defaults, just for now? Perhaps you can get it working at a lower speed and work from that baseline. You say you also updated the BIOS. Could also be that the RAM is not 100% stable with the new BIOS? I understand that the problem occurred with the previous BIOS, so less likely I think.  You could also check your cables as well, just in case one of those is not fully plugged in (check at the PSU as well) and the power consistency is bad due to a high resistance contact on a pin, although I think also less likely from what you say. 

[alue2236]

Hi John, I switched the cpu to a 13900k and it was giving the same result. Also the PSU should be ruled out because I plugged in the psu from another pc and it didn't fix anything. As for the stability of the ram, if I clear the CMOS then it should apply the base ram speed of like 4600MHz so I don't think it's that. Also when I tried another stick of ram that works combined with the not working one, the bios only shows the one that works. Another thing is that I ordered exactly the same motherboard just to see if it's the motherboard that is faulty, and the result was the same (lol). 

[Silent_Scone]

Hi @alue2236 

As JohnAb has suggested, best to remount the CPU first to rule out pin-pad contact issues. If you're using a CPU Contact frame (Thermal Grizzly, etc) best to remove this also.

[alue2236]

Hi Silent_Scone. I took a cpu from another pc and I used the stock ILM, and the result was the same. I think if there was an issue with the mounting pressure then neither of ram would work, but in my case another set of ram sticks work just fine.

[Silent_Scone]

As the system is unable to POST at Optimised Defaults I've moved the thread for the attention of service.

[pndiode]

Works under some circumstances, tried another stick of ram that works combined with the not working one, the bios only shows the one that works.

Try cleaning the ram sticks with an eraser (gold fingers, both sides). 

[alue2236]

Hi, I just tried it, but with no luck. Thanks for the suggestion though

[RickJamesBish]

Have you tried CMOS reset?  

[alue2236]

it was the first thing I did