DDR5 GSkill 6800MT XMP unstable with 14900ks

[FNU0338]

Hi,

I just made a new build with the i9 14900KS,  A Z790 Dark Hero and a kit of 96Gb Gskill F5-6800J3446F48GX2-TZ5RK.

As soon as I turn on XMP I  or XMPII I have some stability issues. The easiest test is to run a cinebench 2024 multicore test and it freezes in less than 10 seconds.

Is there a way to get that stable ? Should I change for another kit or wait for some future bios update? 

[FNU0338]

if anyone does know a good 2 channel or 4 channel kit >64Gb  and > 6800Mt for a 14900Ks please let me know !!! 

[Sarata]

dominator titanium (64GB) has additional XMP 6800. Link

Works for me on Apex Encore and 14900Ks (latest Bios).

[Silent_Scone]

Hi @FNU0338 

The higher density kits require a reasonably good CPU memory controller. 

1. Try XMP II profile as this uses more relaxed memory subsets 

2. Reduce memory frequency to 6000 - 6400MT

3. Try Maximus Tweak Modes 1 & 2.

If no luck, report back.

[FNU0338]

I tried all the XMP options and none of them seems to work stable with the 14900KS.   From what I read on the internet the 14900K does not have the issue with this same kit but the 14900KS does .... 

Is it just that I have to wait for a BIOS update or firmware update? Or this kit will just never work at the desired frequency ? 

If I'm to lower it to 6000 - 6400 I'd rather get another kit.  

My only question about getting another kit is : what kit would work ? 
Reading the Motherboard supported memory kit page it does list some kit that does not even exist  (like the corsair) and the one I have is listed as supported.

[FNU0338]

I tried with another kit of Corsair dominator titanium 96Gb 6600MT and got the exact same result. 
When using either the Corsair kit or the GSkill kit with a single stick it seems to work just fine. 

Does it mean It's just a matter of time and a BIOS update or a firmware update will fix this issue ?

And between the 2 kits which one should I go for :
Gskill F5-6800J3446F48GX2-TZ5RK
or Corsair CMP96GX5M2B6600C32 

For a 2 cas latency difference I'd probably bet on the GSkill 6800 but as you get it I'm clearly not an expert with OC 🙂  so an expert advise would be really appreciated 🙂

[Silent_Scone · Accepted solution]

Hi @FNU0338 

1. Using a single stick reduces the number of channels to the IMC and is easier for the CPU to cope with. The chart below shows the maximum operating frequency for 14th Gen processors. Note that the maximum operating frequency for a Two Slots Per Channel (2SPC) motherboard with single or dual rank modules (SR, DR) in One DIMM Per Channel (1DPC) is 5200MT. Anything beyond this is classified as an overclock, and may require manual tuning due to variance when running the system out of spec. Did you try lowing the frequency to see if this helped stability?

More Information on XMP

2. If needing to ask which kit, I would opt for the slower frequency if you do not want to tune manually. Note that the higher the density, the more likely user intervention is needed.

You can use some pointers from my 8000MT guide which may help you dial in.

Regarding the comments about the KS having issues where the K doesn't, that statement is false. Both the K and the KS are based on the same die. As Intel does not bin their CPUs for memory controller capability your mileage will vary on each sample.

[FNU0338]

Yes, i did lower the frequency down to 6000 but it does not change anything.

at 6000 dual channel  it takes longer to trigger the issue but it happen exactly the same way.

[FNU0338]

Well asus tech support seems to think that it could due to a defective motherboard since i tried 3 kits from the QVL (1 64gb / 2 96gb) lower the frequency , tested each sticks one by one, tested the cpu on intel cpu diagnostics,

They said the default xml should work.

I’ll listen to both you and them and return the highest kit and the mobo. Then if the issue happen again …. Well that’s probably more an issue for them

[Silent_Scone]

That depends. Is the instability still there at Optimised Defaults (after clearing CMOS and not enabling XMP)?