Question Compatibility Issues with High-End PC Build (ROG Z90 Hero Mobo and 128GB DDR5 RAM) ?

[hyperflux]

Hello,

I need some help troubleshooting compatibility issues with my motherboard and RAM (Asus ROG Maximus Z790 Hero motherboard and 2x64GB kits/4x32GB sticks of GSkill Trident Z5 DDR5 6000mHz CL32 RAM), plus some general guidance on how to proceed with the following situation.

Any general advice is appreciated regarding my build, here is a link to my build in PDF form and some relevant screenshots regarding the DDR5 RAM stability/compatibility issues plus my response email: https://drive.google.com/drive/folders/16wcvNS_feuejwcP3GH17MlOONzONviAe

The system is basically as follows: CM HAF 700 Evo case, i9-13900k CPU, RTX 4090 TUF OC/Strix OC GPU (I heard issues about coil whine on this model), ROG Maximus Z790 Hero mobo (next version up is the Xtreme version), 128 GB DDR5 RAM @5200-5600mHz mobo default, 8TB SN850X NVMe SSDs, EVGA 1600W PSU, Corsair H170i Elite liquid cooler w/ LCD display, Windows 11 Pro, 3 years full systems warranty + priority assembly build/cable management).

I'm not sure why only 2/4 sticks work at 5200-5600mHz, the board supports up to 4x 7200mHz DDR4 32GB modules so it should definitely support my 128GB RAM at non overclocked/motherboard default clock speeds. Should I leave the extra 64GB (2 sticks) on standby for now until the potential BIOS update or is this a mistake on their end?

Here's some quick background:

I decided to upgrade to a new high-end desktop build for gaming and productivity in October just as the 40 series GPUs came out (I'm WFH and had a good last couple of years at work so decided to get a solid high-end build).

I've been using a 38" UWD (3840x1600p 21:9 144hz) with a Thunderbolt 3 dock via my Dell XPS17 2020 flagship laptop (10th gen i9 flagship CPU, 64GB DDR4 RAM, RTX 2070 Super MaxQ, 2TB SSD, 4k UHD), but now I've upgraded to a 42" 16:9 4k 138hz OLED monitor (Asus PG42UQ). I have all current gen consoles with HDMI 2.1 as well.

Anyway, my parts finally arrived last week (we were waiting on the RTX 4090 Strix OC this whole time and it never came in presumably due to pin connector issues but he was able to procure me a 4090 Asus TUF OC at the last minute since it's urgent now that I've lost my laptop and therefore have no means of working). I've also been on the lookout for a 4090 FE from Bestbuy (Canada) but kept missing the drops with alerts.

Any other additional input or advice would be greatly appreciated - I should have posted here first in hindsight. I haven't built a proper rig in over 10 years but I did my best in terms of research and was warned about DDR5 stability issues at the moment since it's so new.

Thanks so much for your time and happy holidays!

 

[mmin]

13th gen 1dpc high clock 2dimms

13th gen 2dpc much lower clock officially 4400mt 4dimms

12th gen is 3600mhz 4dimms.. lol
See intel specs

 

[hyperflux]

Upon further research and reading anecdotal info it seems like the only way 128GB DDR5 RAM will work on an i9-13900k/13th Gen Intel/High-End Z790 motherboard is with 4x32GB 4800mhz CL40 sticks (Corsair Vengeance for example) without XMP (which fails at 5200mhz).

Looks like I'll have to stick with a single 64GB kit for now (GSkill Z5 Trident 2x32GB @6000mhz CL32) until a future BIOS update or when single 64GB sticks come out which might take a year or two unfortunately.

The absolute latency difference between the two options is 10.67ns vs 16.67ns so I'm probably better off with the faster memory for the time being. They are upgrading my motherboard from the Maximus Hero to the Maximus Xtreme (Z790) so maybe that'll help compatibility/stability (or at the very least expedite the BIOS update given that it's the highest end motherboard).

 

[johanpmeert]

When using 4 sticks of ram, Always look at the QVL memory list of your mobo. On there you'll only find some Kingston 4x32GB sets @ 5200 speed. So that will be the max. that works. You're even lucky that sets of 4 dimms are even supported.