Showing results for 
Search instead for 
Did you mean: 

Memory not stable on Maximus Z790 formula (new thread)

Level 8

Memory not stable on Maximus Z790 formula @Silent_Scone 

Some moderator (apparently a Super Moderator) , decided to lock my other thread, because I have an opinion that differs from his.

Clearly, Asus does not want true open discussion and you need to accept the opinions of some of the moderator or they just lock the thread..

Based on the poor customer support from ASUS and its Super Moderator, I will make every effort to NOT recommend anybody buying any Asus product.

I will no longer visit the Asus Forums and instead seek support and feedback elsewhere.

Re: Memory not stable on Maximus Z790 formula - Republic of Gamers Forum - 996052 (



Hello Ronvp1

I doubt they locked your thread, the new forum sometimes auto locks threads.

Anyway, I had a read through your thread and you say your memory is stable at 6600MHz but not at 6800MHz.

I see you tried the Dram VDD and Dram VDDQ voltages at 1.47v and it still didn't fully stabilize.

There are five voltages that will help stabilize your DDR5 memory, you already know of two.

1)  Dram VDD voltage - 1.47v

2) Dram VDDQ voltage - 1.47v

3) CPU System Agent voltage - 1.30v

At the bottom of the AI tweaker page click Advanced Memory voltages

4)  IVR Transmitter VDDQ voltage - 1.41v

5) Memory Controller voltage - 1.40v 

Try a test with these voltage settings, if it fails, bump up the Memory Controller voltage to 1.45v and test again.

Any better with these voltage settings?



Nate, thanks..finally some advice and someone who took the time to read my comments. 

I will try you're suggestions tomorrow morning first thing.. what XMP setting you want me to use?


Use X.M.P. I

X.M.P. II is tweaked and may be more of a struggle to get stable.






I tried the suggested voltages (Bios all defaults) with each of the XMP selections, using the timings from the QVL. It does not get stable. I then proceeded with my own timings and it is stable in MemTest386 (Just did 1 cycle), but fails in windows within 5 min both in OCCT and AIDA64. I proceeded with uninstalling several utilities (Armoury Crate, Firestorm (ZOTAC) and Lian-Li L-Connect-3) and rebooted. Again stable in Bios, but Windows keeps failing. 

My good test in Bios is with 1.41V across the 5 settings mentioned above. Any higher Voltages show no improvement. This good test is with the following Timings:  34,39,39,39,84.

Asus timings from the QVL and many other timings fail both in MemTest386 and Windows. 

So I am back on 6600 Mhz. with Voltages at 1.4.  I am very stable and 14900K CPU slightly overclocked and undervolted.

To sum it all up:

  • Timings from the QVL list are not stable (6600 or 6800 Mhz) in Windows
  • My listed timings are stable at 6600 and 6800 with MemTest386 run from Bios.
  • My listed timings are stable for 6400 and 6600, both in Windows and MemTest386

I started this new build with a complete clean copy of windows, but had since installed and uninstalled several utilities (Intel XTU, AIDA64, Chrystal Disk Mark, etc..) and my daily use stuff (Solidworks and other productivity software)

So why the Asus QVL timings do not work with 2 x 48MB, I do not know. I tried 1 identical set of memory (2 x 48), it did not work either, but a 7000Mhz (2 x 32) kit works fine (Non QVL)... I also tried single 48mb sticks and those are stable with no issues at Asus QVL timings. 

In any case, I need to move on from this stuff and make some money!

Nate, thanks for the support!

i. 2x 48GB 6800-7000MT on a 2DPC board is tough on the CPU IMC. 

ii. Memtest 86+ isn’t going to tell you much regarding stability in the OS. Use dedicated tools such as Karhu RAM Test or TM5.

iii. The voltage suggestions given by Nate may be from his own system, or they might just be arbitrarily raised ones in an effort to help you. When it comes to adjusting voltages, sometimes all one can do is point users in the right direction. This is why we refer to it as “tuning” and not simply raising voltages.

Any voltage carrying a signal, for example VCCSA (or System Agent), can be susceptible to too much voltage just as it can too little in terms of what’s valid for a given memory configuration. This is why deviation from the vendors auto ruling can sometimes be necessary. Moreover, the window for what is considered electrically valid becomes narrower the closer to the edge of platform limits we are (when we increase frequency, density and tighten latency).

For better success in achieving "plug and play" overclocking, consider memory kits that are a few
 frequency bins below the motherboard's maximum qualification on the QVL. The higher the frequency and tighter the timings, the more likely manual tuning might be needed to adjust for signal variance between parts, and success with memory kits at or near the top of the QVL validation table will depend largely on the quality of the CPU memory controller. Whereas the QVL shows which kits ASUS have validated as working, they do not have access to every CPU, and this is where the majority of variance comes in to play. 

As Nate has rightly pointed out, 2x48GB @ 6600 on a 4 DIMM board is a respectable overclock.







13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

Super Moderator

Hi @Ronvp1 

 Despite my suggesting manual tuning (which is always a condition when it pertains to overclocking), you suggested it was somehow ASUS's fault and became passive-aggressive. In that instance, the thread had run its course. If you'd accepted what you had already been told rather than posturing,  you wouldn't have needed another user offering the same suggestions with arbitrary values. 

The QVL and XMP do not assure automatic overclocking, no vendor does. This is simply how things are, posturing won't change this fact. Perhaps now you will consider manual tuning given it's been suggested twice in the space of two threads. Remember, our systems are working - we're responding to help you.


Please note that XMP II is not tweaked. 

As per the previous thread, XMP II is the default DIMM profile and often contains more relaxed memory subsets than XMP I - which is the board-optimised profile and the one validated by the memory vendor (QVL) and by ASUS.

13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090



Thank you for clarifying X.M.P. II.


Actually, 64GB 7000MHz is very good.

Going up to 96GB (2x48GB) is adding 32 more GB, adding more capacity puts more strain on the cpu's memory controller and is what I suspect.

Happy with 1 stick (48GB 6800MHz) at QVL settings.

Happy with 64GB 7000MHz.

Not happy with 98GB 6800MHz, the 200MHz less speed apparently isn't enough to make up for the additional 32GB, this is where adjusting voltages can help stabilize it. 

I think you're doing very well with your testing. If you can't get it fully stable, loosening the timings a little as you've done to keep 6800MHz isn't too big of a deal and is what I would do too, or just go with the 64GB 7000MHz kit.   

You could always try manually setting your memory instead of using X.M.P. and see if this gives any better results.



Nate, like I said earlier, I am ok with the 6600, just not happy. The good thing is that the timings for 6600 are better than for the 6800. I am.going to leave it as is and maybe mess with it after you guys had more time to tweak the bios..

Again, thanks for the help

Today, I was looking at Armoury Crate  and noticed the DRAM frequencies are not consistent. Can you please take a look at the attached screen shots and let me know what I am looking at?

Also, there appears to be a bug in the BIOS (1002). The Dram VDD voltage and VDDQ voltages are listed both on the main Tweaker page and under the Advanced memory settings page. When I change those on the main page, it is updating the same listings in the Advanced Memory Page,   But not the other way around. Then After saving and rebooting, The values sometimes have different values..Screenshot 2024-02-28 075446.pngScreenshot 2024-02-28 075612.png