Question Asus rog crosshair viii hero wifi Ram Issues

nollyss

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Nov 20, 2013
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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
Any help with this would be most appreciated.
Thanks
Nay
 

nollyss

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Nov 20, 2013
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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
Any help with this would be most appreciated.
Thanks
Nay
 

nollyss

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So the old mix and matching of ram is always a chance taken especially with AMD systems. If you use 32gb set separately, do you have this problem? I would bet they work fine independently but not together.
Hi, I just 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?
If I was to purchase another 64GB Dual kit and put that in with my current 64GB Dual kit will I still have this problem?
 

neojack

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All you ram needs to be exactly the same for XMP to work correctly. At least it is the case for my experience with like 3 or 4 rams kits i used on a ryzen 1800x, then on my 2700x

In the end i just decided to buy an AMD certified "Flare X" 64GB kit, no problems since.

YMMV with newer CPUs
 
When you buy memory, it is always best to buy the amount you want as one kit, especially for AMD systems. Intel systems you can usually get away with buying the same exact model and adding more but not mixing different models, even if the different model has the same timings, cl, and voltage. The answer to your question to buying another 64gb kit of the same model, it will probably work, but I cannot guarantee it will. Buying different kits of the same model can cause problems because the manufacturer may have changed parts on the memory that was not used on the prior memory you bought. When you buy memory as one kit it ensures the memory was all made at the same time and used the same parts on each one.
 

nollyss

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When you buy memory, it is always best to buy the amount you want as one kit, especially for AMD systems. Intel systems you can usually get away with buying the same exact model and adding more but not mixing different models, even if the different model has the same timings, cl, and voltage. The answer to your question to buying another 64gb kit of the same model, it will probably work, but I cannot guarantee it will. Buying different kits of the same model can cause problems because the manufacturer may have changed parts on the memory that was not used on the prior memory you bought. When you buy memory as one kit it ensures the memory was all made at the same time and used the same parts on each one.
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.
 
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DSzymborski

Titan
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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.
Yeah, there's no guarantee that two different kits, even with the same branding, will work together; no two sticks of RAM are truly identical, so RAM is sold together because it's been tested to be able tow ork togther. But with similar RAM, you do have a very good chance of it working out, so I'm glad that you were on the lucky side there.
 
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