Asus Z790-Plus Wifi DDR5 GSkill Trident Z5 4x32 XMP not working!

[audi911]

Hello,
I just bought my motherboard and 128GB (4x32GB) of GSkill DDR5-6400 CL32-39-39-102 1.4V Memory.
The system cannot boot with XMP1 or XMP2 profile. XMP off is no problem. The issue is the RAM runs at 4800 with no XMP. I bought this RAM specifically because it's 6400 and the motherboard is clearly rated to support that memory
4 x DIMM, Max. 128GB, DDR5 7200(OC)/7000(OC)/6800(OC)/6600(OC)/6400(OC)/ 6200(OC)/ 6000(OC)/ 5800(OC)/ 5600/ 5400/ 5200/ 5000/ 4800 Non-ECC, Un-buffered Memory*
I tried 3 BIOS versions including the latest one and it does not work.
Does anyone know how to make fast memory work on this board?
Is it the board the issue?
I don't believe it is the memory because no XMP works fine.
Any help would be greatly appreciated.
Thanks!

[Murph_9000]

Assuming you have the TUF board and a 13th gen K/KF-series CPU, there are no 4 DIMM configs for DDR5-6400 on the TUF GAMING Z790-PLUS WIFI Memory QVL. The "socket support" column must be "1,2,4" for a 4 DIMM config; if it is "1,2", that's a 2 DIMM config. The fastest 4 DIMM config on the current QVL for that board and a 13K CPU is DDR5-6000, but that's for 4x16GB; the fastest 4x32GB config on the QVL for a 13K CPU on that board is DDR5-5200. If you have a 12th gen or non-K CPU, there are no 4 DIMM configs on the QVL.

That doesn't mean that you absolutely won't be able to get it to work; it might work with some effort. 4 DIMM configs are harder to get stable than 2 DIMM configs. I suggest trying some speeds between 4800 and 6400, as people have reported some success with 4 DIMM configs and overclocking a bit below the advertised XMP overclock speed. N.B. you need to run a long memory stress test to be certain that it's stable; it's possible to have memory overclocks that can boot but cause crashes later, if they are just a little too fast.

I'd start with trying it at 5600 with the XMP timings, see if that's stable.

In general, you can't have the fastest memory speed and the highest capacity simultaneously. Bigger DIMMs (i.e. 32GB) are harder to overclock than smaller ones, and combining that with a 4 DIMM config is even harder. Note also that combining multiple kits of memory is another thing that can be problematic or add to the difficulty; even if they are identical part numbers.

Lastly, you might find some improvement by updating your BIOS (update the Intel ME (Management Engine) and ME driver first).

[audi911]

Hello thanks for the input.
I've never actually overclocked or played around with the XMP profiles.
Is there anything specific that I need to do, i think that when I select XMP it auto populates everything. Am I able to change anything once the XMP profile is loaded?
Would you know what I need to touch when it comes to other specs when I want to play around with the settings to get the ram to run at different speeds?
Thanks!

[Murph_9000]

Yes, you can normally adjust certain things after enabling XMP. Your BIOS will be a bit different to mine (TUF vs. ROG Crosshair), but the basic ability to adjust the RAM speed should be there. You'll want to be in Advanced mode (not EZ mode), and there should be a speed setting a little further down the page from the one that enables XMP. Enable XMP first, which will load the XMP profile/timings, then adjust the speed to see what does and doesn't work.

It's possible that you may need to loosen the timings a little as well (increase the numbers), but try just the speed first to see if you can get any success going above 4800. Looking through the QVL for your board, most of the SK Hynix 32GB DIMMs listed are running at 40-40-40-80. Yours are 32-39-39-102. I'm not an expert on the memory timings, but I'd probably try to see how it behaves on 40-40-40-80 or 40-40-40-102. There should be a memory timings tuning sub-page a bit below the setting that lets you change the speed.

Beyond that, there's the voltage, but your G.SKILL XMP profile is already quite high at 1.4V, and higher than the other 32GB DIMMs on the QVL. I'd be cautious about going any higher than that.

Lastly, I know we'd all love to have 128GB, and we'd all love it to be super-fast, but ask yourself if you actually need that much. 128GB is certainly far more than you need for pretty much all current gaming. Would you be better to have 64GB (2x32GB) running fast, or 128GB running slower? I don't know how you use your machine, what your needs are, etc. Only you can make that choice, but you need to ask yourself that question.