Asus ROG Strix Z390-H motherboard Max RAM

[Denjoe]

Hi all,

I have a custom water cooled pc with I9-9900k on an Asus Strix Z390-H motherboard.

Currently i have 4x8gb rams on it. I need min 128gb ram due to running some LLM models on it.

Z390-H manual says max 4x16gb rams are supported. Is this true? Can’t I just install a 1x32gb ram in there ? Did anyone tried increasing the ram capacity beyond 16gb single sticks? 

[Nate152]

Hello Denjoe

The Tech Specs show the ROG Strix Z390-H Gaming motherboard supports a maximum of 128GB of memory.

If capacity is important, go for a low frequency such as 2133MHz - 2666MHz to have a better chance of it working without much fuss.

Be sure to purchase a single 128GB memory kit.

[Denjoe]

Hey , 

Do you have a link to that website when i go this website it says 64gb only ? 

https://rog.asus.com/au/motherboards/rog-strix/rog-strix-z390-h-gaming-model/spec/

[Denjoe]

Hmm Nate, interesting. I found this link;  (which is probably where you screenshotted it)

https://rog.asus.com/motherboards/rog-strix/rog-strix-z390-h-gaming-model/spec/

Which shows 128gb ram. I wonder if I'm safe to buy 400$ worth of ram just based on this? 

[Nate152]

Yes, G.Skill has a 128GB 2666MHz memory kit on their QVL for the ROG Strix Z390-H Gaming.

F4-2666C19Q-128GTZR - QVL - G.SKILL International Enterprise Co., Ltd. (gskill.com)

[Nate152]

Sure, here you go.

ROG STRIX Z390-H GAMING | Motherboards | ROG Global (asus.com)

[Denjoe]

Hmm, makes sense actually. I mean you are probably 90% right since even the qvl shows support for it up to 128gb and also G.Skill also listed it. 

I compared both pages, it looks like the difference is under expansion slots. AU page shows 2xpce with x16. But the international one shows 1xpcie with 16x support. So I wonder if that additional PCI-E 16x lane caused them to reduce their support for max total ram support from 128gb to 64gb? 

I also asked this to chat gpt but no luck, it concludes that it was a webpage error 🙂 

[Nate152]

Yes, it's PCI-E 1x16 as the cpu has 16 PCI-E lanes.

[Denjoe]

Yes that's what made me uncomfortable. Since mine has two 16x pcie lane like in the au link, it's physically different than the other one. But somehow QVL's won't show difference in between. I'm no expert but just worried that the au one indeed might be only supporting 64gb ram. I wrote an email to tech support. Hopefully they will return in 48 hrs. I will update here later in case if anyone else hits the same wall. 

[Nate152]

Having a look at the AU site, it's saying there are 2x16 PCI-E 3.0/2.0 slots (2.0 being backwards compatible), they can run at 1x16 for one gpu or 2x8 for an SLI configuration (two nvidia gpu's).