DDR5 XMP causing No-Post

[RiknRoll]

Hi guys and gals, I know there are a few posts out there with similar problems but wondering if I've missed any solutions as so far everything I've tried hasn't worked - which did work for some others. PC seems to work ok so far only if XMP is turned off. Turning XMP on causes simple black screen on boot. It then seems to try to restart itself a few times if I leave it 5-10 mins and eventually comes up with a screen to restore factory defaults in the BIOS. 

Specs:
i7 12700K, Noctua DH15 heatsink.
Gigabyte Gaming X
2x16GB Kingston DDR5 6000 40-40-40-80
EVGA 3080 ti XC3 Ultra
Samson 980 Pro 1TB
Corsair RM 850x
Win 11 Home 

To confirm, the RAM is loaded in slots A2 and B2 (as per manual), and is also listed on Gigabyte QV list. The heatsink makes it difficult to remove the RAM without pulling the heatsink off, which obviously I've been trying to avoid.
I've updated the BIOS via the gigabyte @BIOS windows utility to the latest F6a, which likewise didn't help, though I understand that fixed it for most people, but likewise most similar problems i've seen reported have been with DDR4.
All other drivers are updated to be the most recent. 

Thanks for any more suggestions you may have! I've been waiting for what seems like an eternity to get a VR gaming set-up running, first I had a 6 month wait for a GPU, then my old PC grenaded, totally killed both its SSD's and now its been over 2 months wait to get all the parts for this new system, so I'm understandably anxious to get it running!
 

[DoctorNick]

Not that odd. You motherboard supports up to 6000mhz (OC) and CPU up to 4800mhz from factory. XMP sometimes work with lower clocks, but if motherboard only goes up to 6000, then you can expect to manually dial this in. I would try manually setting 6000mhz and primary timings aka 40-40-40-80 and then leave the rest on auto. You can also get the full timings table by downloading Aida64, in Aida go to motherboard->SPD and then take a photo or write down timings for 6000. Might also have a profile for slighty lower clock speed. 

[RiknRoll]

2 minutes ago, DoctorNick said:

Not that odd. You motherboard supports up to 6000mhz (OC) and CPU up to 4800mhz from factory. XMP sometimes work with lower clocks, but if motherboard only goes up to 6000, then you can expect to manually dial this in. I would try manually setting 6000mhz and primary timings aka 40-40-40-80 and then leave the rest on auto. You can also get the full timings table by downloading Aida64, in Aida go to motherboard->SPD and then take a photo or write down timings for 6000. Might also have a profile for slighty lower clock speed. 

Awesome, thank you. Will try it the moment I get home, and will check out Aida, it's not a program I know of

[RiknRoll]

played a bit more with it -  manual overclock to 6000 didn't work, though I might have missed a detail, so I may back to it to solve (the perfectionist in me). Very strangely it seems to be accepting a Hynix XMP booster profile of 5600MHz/CL36, but won't accept the Hynix 6000Mhz/CL40 profile. That said if my maths are correct 5600/36 actually gives a slightly lower latency time, so I may well just settle for this! 

I still need to run benchmarks and tests to see stability however.   

[DoctorNick]

11 hours ago, RiknRoll said:

played a bit more with it -  manual overclock to 6000 didn't work, though I might have missed a detail, so I may back to it to solve (the perfectionist in me). Very strangely it seems to be accepting a Hynix XMP booster profile of 5600MHz/CL36, but won't accept the Hynix 6000Mhz/CL40 profile. That said if my maths are correct 5600/36 actually gives a slightly lower latency time, so I may well just settle for this! 

I still need to run benchmarks and tests to see stability however.   

However it might give slighty lower bandwidth. But yes 12.85 vs 13.33ns.

You might be able to run with higher voltage on memory controller, but your problem is quite normal. I personally use a similar setting as I cant max out my memory to factory 4400@cl19. Instead I run 3733@cl15 or 4000@cl17/16. I found 3733 to perform better with lower voltage on the memory controller.

[RiknRoll]

Thanks for your input and help on this, its much appreciated. Incidentally, Gigabyte support actually have come back to me pretty quickly, saying "it should work" lol, I guess it's the silicone lottery we play.