RAM for ROG Maximus Z790 Dark Hero

[wengang1]

Hi all.

I'm planning my build and I'm pretty much done.

One thing I can't sort out is the RAM for the Z790 Dark Hero.

I know what this website says about the RAM it can take and the speed it can handle, but I see nothing but refutations of this information everywhere I look.  Basically, the gist of the contradictions is that the board can't take four 48GB sticks of DDR5 (the only way I can think of getting the advertised 192GB) and remain stable, it can't get anywhere near the 8000 MHz advertised, and there are several other constraints and limitations that make the specs on this site inaccurate.

Well, I don't want to start is discussion on any of that because I'm not a RAM expert and the more I read about what this mobo can and can't do in terms of RAM, the more confused and less confident I feel about the board.

What I want to know (please) is if you are using this board and your RAM is working fine, please tell me exactly what kit you purchased and in what configuration (slots) you installed it.  That will be WAY more helpful to me than explanations about why something will or won't work.

Thanks all.

[Nate152]

Hello wengang1

The thing is, because all cpu's are not created equal, someone else's memory kit may or may not work. Higher speed memory such as 8000MHz will require a 13900k/14900k with a very good memory controller as stability falls mostly on the cpu's memory controller.

I would only attempt 8000MHz memory on the ROG Maximus Z790 Apex Encore.

So to be safe, somewhere in the 7200MHz range should be doable with a decent 13900k/14900k, the KS cpu's should be slightly better as they are binned.

X.M.P. is not guaranteed to work as plug and play, higher speed memory may need manual voltage tuning.

As an example here is a G.Skill Trident Z5 32GB 7200MHz CL34 memory kit. I'ts two sticks, they would install in the A2-B2 slots (2nd and 4th slots from the cpu).

F5-7200J3445G16GX2-TZ5RK - QVL - G.SKILL International Enterprise Co., Ltd. (gskill.com)

[wengang1]

Thanks for the reply.  I"m  not stuck on the idea of getting 8000 MHz.  This new build will already be an extreme upgrade from the current one I built over 10 years ago. I am planning to buy the 14900KS. I just want the build to be stable and not have a  weak link or a timebomb in it.  I'm not very savvy with XMP or setting voltage, so the more plug and play the better for me. I would like to maximize RAM capacity, but I have even seen where people couldn't get 128GB to work on  this board that boasts 192GB.

[Silent_Scone]

Hi @wengang1 

If needing to ask such questions and are not familiar with memory OC it's best to stick with memory kits which are validated on the QVL.

The board works with 192GB just fine, however, the frequency range past operating defaults depends on the CPU sample and assurances cannot be given due to variance when running components out of spec.

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 into play. 

Anything beyond the below is considered an OC.

[Nate152]

Ok,

Are you building a gaming pc or work pc?

If building a gaming pc, lower capacity and higher speed is what you want.

If building a work pc, then opting for higher capacity means you'll have to sacrifice speed.

As an example, here is a Corsair Vengeance 192GB (4x48GB) kit, it's 5200MHz. Comparing the two memory kits, as you can see, more capacity will always = slower speed.

VENGEANCE® 192GB (4x48GB) DDR5 DRAM 5200MHz C38 Memory Kit — Black (corsair.com)

[wengang1]

Thanks all.

The table is very helpful now that I understand everything over 5600 is overclocking.  The 48x4 Corsair 5200 speed sound perfect for me.  I was just concerned that multiple forum posts on the internet have comments from people who couldn't get 4x48 or even 4x32 to work.  I guess that means they were going for much higher speeds.  

I'm not building a gaming rig and I never overclock.  I didn't mention that because I get the inevitable "Then why are you buying this mobo/cpu/etc."  I just want to build a really high end computer, but a lot has changed in hardware since I built my last one.  I think I have my answer.  Thanks again.

[Silent_Scone]

Hi @wengang1 

Understood. In that case, yes, the table should clarify what's considered to be overclocking. A lot of the posts you're referring to are likely users purchasing high-density kits and expecting 1. Either to be able to combine them and then run them overclocked 2. Expecting to always be able to achieve the kits validation frequency [either without manual tuning or at all]. Running the kit at stock should be no problem at all.

[achugh]

Hi @wengang1 I am using this board with 192GB RAM without any issues. My kit is from the QVL. More details about my build are in https://rog-forum.asus.com/t5/gaming-motherboards/can-asus-support-fix-realtek-audio-drivers-with-bo... post.