Can i run 128GB RAM @ 3600MHZ CL18 on my Dark Hero MB?

Fadi Obaji · 2 Jan 2021 at 10:59

Hello,

I have the following:
Motherboard: Asus ROG crosshair VIII DARK HERO
CPU: Ryzen 5950x

Now i want to get the RAM and i need 128GB, i've been researching this kit: F4-3600C18Q-128GTZN

Now i checked the QVL of the Dark Hero motherboard, the RAM kit doesn't seem to belong there. I don't understand the QVL actually, if a RAM kit doesn't belong to the mobo QVL, is it 100% not going to work at the advertised XMP values?

Did anyone try to overclock 128GB ram on dark hero?

Can i make this kit run at 3600MHZ CL18?

Minstadave · 2 Jan 2021 at 11:01

4 dual rank DIMMS on Zen 3 isn't easy to run at high speed. It's possible but may need some tweaking.

Fadi Obaji · 2 Jan 2021 at 11:07

Minstadave said:
4 dual rank DIMMS on Zen 3 isn't easy to run at high speed. It's possible but may need some tweaking.

Hey, thanks for your reply!

What do you mean by tweaking?

And if they can't run at 3600MHZ CL18, they'll run at the DDR4 default speed?!

Minstadave · 2 Jan 2021 at 11:11

Im not sure how strong the Dark Hero is for 4xDIMMs, it seems some X570 boards are better than others. It also depends on your individual CPUs memory controller.

By tweaking I mean you may have to tinker with SOC volts and RAM subtimings to get it to run at those speeds.

Worst case scenario you may to dial back from 3800mhz a bit.

Fadi Obaji · 2 Jan 2021 at 11:18

Minstadave said:
Im not sure how strong the Dark Hero is for 4xDIMMs, it seems some X570 boards are better than others. It also depends on your individual CPUs memory controller.

By tweaking I mean you may have to tinker with SOC volts and RAM subtimings to get it to run at those speeds.

Worst case scenario you may to dial back from 3800mhz a bit.

So they might not work at 3600MHZ CL18 but they might work at let's say 3400MHZ CL16?

Minstadave · 2 Jan 2021 at 11:32

Fadi Obaji said:
So they might not work at 3600MHZ CL18 but they might work at let's say 3400MHZ CL16?

Correct.

Mr Evil · 2 Jan 2021 at 12:30

Minstadave said:
Im not sure how strong the Dark Hero is for 4xDIMMs, it seems some X570 boards are better than others...

The main factor affecting that is whether the DIMMs are connected with daisy chain vs. T-topology. T-topology allows higher speeds with all 4 slots populated. The Dark Hero is daisy chain.

Minstadave · 2 Jan 2021 at 12:32

Mr Evil said:
The main factor affecting that is whether the DIMMs are connected with daisy chain vs. T-topology. T-topology allows higher speeds with all 4 slots populated. The Dark Hero is daisy chain.

I think every X570 board is daisy chain so it has no real world significance. The Taichi was rumoured to he T-Top but retail boards were daisy chain.

The 8 layer PCB boards seem stronger than 6 layer PCB boards when it comes to 4xDR. Some manufacturers seem to have tuned their boards better too. The Unify is meant to be one of the best for 4xDR.

Mr Evil · 2 Jan 2021 at 14:00

Minstadave said:
I think every X570 board is daisy chain so it has no real world significance. The Taichi was rumoured to he T-Top but retail boards were daisy chain...

There are multiple ASRock boards listed as T-topology in the spreadsheet I linked to. I have no way to verify what they are in reality though.

WJA96 · 2 Jan 2021 at 14:08

Mr Evil said:
The main factor affecting that is whether the DIMMs are connected with daisy chain vs. T-topology. T-topology allows higher speeds with all 4 slots populated. The Dark Hero is daisy chain.

That's a very handy spreadsheet. Thanks for posting that.

Minstadave · 2 Jan 2021 at 23:04

Mr Evil said:
There are multiple ASRock boards listed as T-topology in the spreadsheet I linked to. I have no way to verify what they are in reality though.

I believe its incorrect and all their retail boards were daisy chain.

Joxeon · 2 Jan 2021 at 23:44

4 dimms are harder to run than 2 and 32gb dimms are harder to run than 8 and 16gb etc.

If it's not on the qvl than it just means that it's not been tested and confirmed to work but that doesn't mean it won't.

zx128k · 4 Jan 2021 at 22:13

Some motherboards wont support 4 x DIMMs with some memory, only 1 or 2 sticks. You should always check your motherbords QVL memory list for compatibility before buying memory kits. Also you can create a customer thread on the forums and ask overclocker staff and they will advise you on the best kit for your motherboard.

With 8-pack memory 3600MT/s CL14 with four DIMMs slots full. I can't go above 3600MT/s CL14 on a z490 motherboard. Before over 4200MT/s was no problem.

In my motherboad QVL the RAM does not appear https://rog.asus.com/motherboards/rog-strix/rog-strix-z490-g-gaming-model/helpdesk_qvl_memory/

but there is
Team TF10D48G3600HC14CBK 8GB 3600 3600 SS Samsung 14-15-15-35 1.45 1,2,4

This looks like one stick of the 8-pck kit. Note that 4 x DIMMs are supported. Normal timings and frequency.

Its even supported in a DR configuration.

Team TF10D416G3200HC14BBK 16GB 3600 3600 DS Samsung 14-15-15-35 1.45 1,2,4

So I got 4 x DIMMs and everything worked fine so far.