ROG MAXIMUS Z790 HERO Vs DDR5 Vengeance 4x32GB 6800

[Furlooze]

Hello world !

It seems that I'm facing same issue as tons of users/gamers ... & I read a ton of different solution or workaround (even some who have downgraded to 64 instead 128 & waiting for a new firmware ?!? wtf ?

I Build 2 rendering computers , both exactly same config

ROG MAXIMUS Z790 HERO -  i9-13900k -  DDR5 Corsair Vengeance 4x32GB 6800  - Corsair MP700 2To M2 

Upgrade UEFI to 1501 

If I set UEFI "Load Optimized default" : DDR5 is detected as 3800 , desktops run smooth but obviously DDR5 benchmarks are not those expected ...

If I load XMP2 --> all settings are defined exactly as it  should ... (latency, voltage, speed,...)  but error status 77 after save settings & reboot 

Exactly same issue encounterd on both computers  

Am I missing something in UEFI settings ?

Thx !

[Nate152]

Hello Furlooze,

In some cases, high speed/high capacity ram will need a voltage boost.

But, in your case, it looks like you're combining two 64GB 6800MT/s memory kits. This equates to 128GB at 6800MT/s, this has not been tested or validated as a single memory kit.

You'll have to settle for a lower frequency with 128GB.

[Furlooze]

Indeed I should read the qvl memory list before ... the only 128 kit supported is a Kingston ... & 5600 max ... 

for 6800, it's 2x16 Gb MAX , whatever the brand ... was not clear at all when reading system board properties 

(I need 128, lot of Vm's )

I'll try same settings as the supported kingston kit (5600)  40-40-40-80 1.25 

With a little bit luck, the chipset will be the same between these kits (SK Hynix) & it should do the trick 

Finally , as always : RTFM ! (my bad)

[Nate152 · Accepted solution]

 I can help you with some voltages and there are five voltages that will help stabilize your ram.

Here is what I would try, do you have a pencil and a piece of paper ready?

In the bios on the Ai Tweaker page...

1) Reset the bios to defaults - F5 key.

2) Set the Ai Overclock Tuner to Manual.

3) BCLK Frequency: Dram Ratio - 100:100

4) Memory Controller: Dram Frequency Ratio - 1:2

5) Dram Frequency - 5600MHz

6) Dram VDD voltage - 1.40v

7) Dram VDDQ voltage - 1.40v

8: CPU System Agent voltage - 1.275v

At the bottom of the Ai Tweaker page click Advanced voltages:

9) IVR Transmitter VDDQ voltage - 1.40v

10) Memory Controller voltage - 1.40v.

If it boots at 5600MHz, you can slowly work up the Dram Frequency until it becomes unstable, then back it down a step.

But first, how does it go trying this at 5600MHz?

[Furlooze]

Dude you made my day ! It works perfectly @ 5600 with your settings , reproduced on the second workstation : confirmed

Launch VRAY Benchmark (CPU only) (in a hosted VM) score >25700 ! more than double than my previous rendering ws. (i9 11900k) on root OS (no VM)

Also suggested by LukeJoseph, MCE set to OFF ! --> Benchmark fall to >25700 . Negligeable so I prefer to leave it on OFF

Stress tests PassMark without any issue (Usually used to check long term cooling capabilities) 

Y-Crunch downloaded , basic tests launched succesfully, but I need to read LukeJoseph post to understand how to launch VST+VT3 multiples pass tests   

[Nate152]

That's great !

I'm not sure how much headroom is left, but you can try the next highest Dram Frequency. If it fails, just back it back down to 5600MHz.

[LukeJoseph]

Keep in mind there are no 4 DIMM DDR5 Kits, so XMP is not really a thing when running 4 dimms. There is some good advice already posted here, but please make sure your fully test your ram. Even if your ram is slightly unstable it may not crash windows/games but could corrupt your Windows installation over time.

Here is a link to the method that I use. https://www.overclock.net/threads/official-intel-ddr5-oc-and-24-7-daily-memory-stability-thread.1794... in my experience nothing really beats y-cruncher VST+VT3 for quick testing. But run the 5-6 passes twice, intels IMC's can be so temperamental, where you may pass 5-6 passes, close y-cruncher run it again and fail in pass 1. Also ensure you enable Intels power limits (MCE Off is fine) for y-cruncher as it can pull some significant power.