Asus rog crosshair viii hero wifi Ram Issues

[Nay]

Hi,
Purchased 64GB (2x32GB) Corsair DDR4 Vengeance LPX Black, PC4-28800 (3600), Non-ECC Unbuffered, CAS 18-22-22-42 (CMK64GX4M2D3600C18 ) Dual Kit and 32GB (2x16GB) Corsair DDR4 Vengeance LPX Black, PC4-28800 (3600), Non-ECC Unbuff, CAS 18-22-22-42 (CMK32GX4M2Z3600C18) Dual Kit.
On my Asus rog crosshair viii hero wifi Motherboard I can only get these to run stable when I select Auto mode which puts the ram at 2133MHz a long way of the rams capability of 3600MHz on this Motherboard.
The CPU I am using is AMD Ryzen 9 3950x
I tried the 64GB (2X32GB) Dual kit on there own without the 32GB Dual kit and I can enable DOCP and get 3600MHz.
So is the issue because the 4 ram slots are using a 64GB Kit and a 32gb Kit at the same time even though they are same spec just different size GB?
If I was to purchase another 64GB Dual kit and put that in with my current 64GB Dual kit to give me 128GB will I still have this problem as I want to get the maximum ram the board can take which is 128GB?

 

[Legion]

Try with them all in setting them manually to 2667 and work up from there. (enable XMP and drop the speed to 2667) 64gb kit in A1, B1 and 32gb kit in A2, B2
It's highly likely here you're just hammering the memory controller too hard trying to run them all at 3600.

https://www.amd.com/en/products/cpu/amd-ryzen-9-3950x

Scroll down a bit and you'll find:

Max Memory Speed
2x1R DDR4-3200
2x2R DDR4-3200
4x1R DDR4-2933
4x2R DDR4-2667

The 32gb kit is highly likely to be Single rank (1R) Especially if you've bought these recently.
The 64gb kit is Dual rank (2R), so it's listing 2667 as the max officially supported. You'll just have to tune these manually until you find the limits of the Memory controller on your 3950x. 2667-3200 should be doable.(even with mixed rank kits)
You might even get near 3400, but you'll have to do all this manually.

It could also be some imbalance between trying to mix single rank and dual rank kits. but you'll still get more out of them tuning manually.
Do some testing first before you decide to throw more money at another 64kit.

You can also now find 5950x CPU's for bargain prices on the second hand market. The memory controllers on the 5000 series CPU's are much stronger than they were on the 3xxx CPU's.
If you want 128gb ram, you'll have better luck at running them at higher speeds with a 5xxx CPU.

 

[Nay]

Try with them all in setting them manually to 2667 and work up from there. (enable XMP and drop the speed to 2667) 64gb kit in A1, B1 and 32gb kit in A2, B2
It's highly likely here you're just hammering the memory controller too hard trying to run them all at 3600.

https://www.amd.com/en/products/cpu/amd-ryzen-9-3950x

Scroll down a bit and you'll find:

Max Memory Speed
2x1R DDR4-3200
2x2R DDR4-3200
4x1R DDR4-2933
4x2R DDR4-2667

The 32gb kit is highly likely to be Single rank (1R) Especially if you've bought these recently.
The 64gb kit is Dual rank (2R), so it's listing 2667 as the max officially supported. You'll just have to tune these manually until you find the limits of the Memory controller on your 3950x. 2667-3200 should be doable.(even with mixed rank kits)
You might even get near 3400, but you'll have to do all this manually.

It could also be some imbalance between trying to mix single rank and dual rank kits. but you'll still get more out of them tuning manually.
Do some testing first before you decide to throw more money at another 64kit.

You can also now find 5950x CPU's for bargain prices on the second hand market. The memory controllers on the 5000 series CPU's are much stronger than they were on the 3xxx CPU's.
If you want 128gb ram, you'll have better luck at running them at higher speeds with a 5xxx CPU.

I tried manual settings but even if I slightly increase the frequency just above 2133MHz I start having issues.

 

[Tetras]

I tried manual settings but even if I slightly increase the frequency just above 2133MHz I start having issues.

What timings are you using?

Did you increase the DRAM voltage?

There may be other things you need to tweak to get these stable.

Does CPU-Z say they are the same memory manufacturer?

 

[Nay]

What timings are you using?

Did you increase the DRAM voltage?

There may be other things you need to tweak to get these stable.

Does CPU-Z say they are the same memory manufacturer?

Hi,

I purchased an additional 64GB (2 X 32GB) of Ram which turned out to be the exact same spec as my current 64GB (2 X 32GB) Ram sticks and works fine using the DOCP overclock option and running at 128GB of Ram using all four Modules at the full 3600MHz.