DRR 5 XMP unstable where to start with adjustment.

[Gun Jam]

Hello

I am running a new CPU (intel 13900k)

New memory: G.SKILL Trident Z5 RGB Series 32GB (2 x 16GB) 288-Pin PC RAM DDR5 6800 (PC5 54400) Desktop Memory Model F5-6800J3445G16GX2-TZ5RK

New MB: ASUS ROG Strix Z790-E Gaming WiFi 6E LGA 1700

This memory is listed on the asus QVL and Gskill QVL

The issue is im running 4 sticks at 16gb each for 64gb total. I missed that its only certified at 2 sticks apparently.

Ive had zero issue with it in normal profile its ran a full day+ with out missing a beat and passed a few cycles of memtest64 with no issues.

If I place this memory in XMP profile it runs just long enough to make you forget there's and issue in most cases but right as you forget it will bsod or the app will freeze... some issue like that. If you attempt to run memtest64 it will eat dirt straight away usually during the mem count total.

my guess is with a bit of adjustments I can get XMP to run. But im not sure where I should start my guess would be to boost voltage but im not sure how much I should be moving up each attempt and whats safe upper limit.

Tradesman has help with a few of my systems in the past not sure if he's still active here but please advise how I should proceed.
Thanks!!

[emissary42]

With four modules you will probably have to reduce the frequency. If you were able to boot into Windows at DDR5-6800 with 4x16GB, probably just one or two steps. Trying to stabilize four DIMMs @ 6800 would likely require a deep dive into memory timings, training options and voltages. Even then, it might not work out in the end.

[Gun Jam]

Thanks for the info. I loaded the XMP profile and then began to reduce frequency until it would pass memtest64 for 2hrs no faults. At 6000 It appears stable. Considering that im 800 Mhz off of where it could run im wondering how to proceed now.

I really do want 64gb.
I see that even with 2 sticks at 32gb each nothing is supported above 6400. So really im only 400 off of what I could be getting with say F5-6400J3239G32GX2-TZ5RK
If I know its stable at 6000 and was kind of stable at 6400 could we move on to boosting a voltage or is it chill out time and see if someday asus can figure out a bios with an xmp profile that is more stable??

Thanks!

[emissary42]

It is unclear if the frequency with four modules can catch up to 2x32GB in the primary slots, just from BIOS updates. That could also very well be a hardware limitation, of either the CPU (memory controller) or the motherboard (PCB). So for now my recommendation would indeed be going with a 2x32GB kit like the F5-6400J3239G32GX2-TZ5RK.

A while back there was an announcement for higher frequency 2x32GB models. It is however very likely, that those would only be compatible with 2-DIMM motherboards like the Apex or Dark.

[Gun Jam]

Okay so if I did go with the 2x32GB kit like the F5-6400J3239G32GX2-TZ5RK.

Is it worth the effort to return for 400mhz?
Is there a way to "see" how a 400mhz change would impact VR games like DCS (which is known for being a murderer)?
If I set frequency to 5600 ran a benchmark then tested at 6000 could I expect the same gains from 6000 to 6400? Are gains linear?

Thanks for your help!

[emissary42]

You should be able to find reviews that include performance results for both DDR5-6000 and DDR5-6400. I am not sure though, if your VR games are part of the usual benchmark set anywhere. You could however test for yourself, how big the difference between both frequencies actually is, with 2x16GB in the primary DIMM slots.

Most people probably wouldn't bother to swap the memory, unless they're severely limited by memory bandwidth or hunting for HWBOT points / trophies.

[Gun Jam]

That's a good idea.

I'll do a bit of testing but I'm suspecting that I'll probably swap it for the 2x32GB kit F5-6400J3239G32GX2-TZ5RK. Probably because at the end of the day I might as well get what I pay for...even if thats bit irrational if one considers the bigger picture. Im a bit concerned that bench marking memory maybe difficult... I'll look into some possible methods.
Thanks again!