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XMP DOES'T WORK on ASUS ROG STRIX Z790-E GAMING WIFI II WITH CORSAIR VENGEANCE 16GBx4

Angel777
Level 8

hi!

i istalled 64gb ram :

CORSAIR VENGEANCE RGB DDR5 RAM 32GB (2x16GB) 6400MHz CL32 Intel XMP WHITE (CMH32GX5M2B6400C32W)

+ CORSAIR VENGEANCE RGB DDR5 RAM 32GB (2x16GB) 6400MHz CL32 Intel XMP (CMH32GX5M2B6400C32) 

The only different is the color, two are in white version..

Xmp, or Xmp2 does a crash on post or immediately soon in windows11,

there's a way to resolve? thanks

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15 REPLIES 15

cekeu
Level 12

Hi
We cannot mix two references. You should buy a memory kit of 4 strips or two strips but not mix 2 x 2 memory kits. for example we should take this one:

https://www.corsair.com/us/en/p/ddr5-ram/cmk64gx5m4b6400c32/vengeance-64gb-4x16gb-ddr5-dram-6400mhz-...

Sorry but in this case, the memories are technically identical, only the white aesthetic changes in this case

ram1-black Dimm_B2ram1-black Dimm_B2

 

ram2-white Dimm_B1ram2-white Dimm_B1

 

ram3-black Dimm_A2ram3-black Dimm_A2

 

ram4-white Dimm_A1ram4-white Dimm_A1

 

 

MP/EXPO Validity and Mixing Modules: Combining and mixing memory kits isn't supported by memory or motherboard vendors. This is because memory vendors bin and validate the memory kit in the density in which it is sold. If you combine memory kits, the overclocked settings in which the kit is validated for XMP/EXPO are no longer valid. Purchase a single kit validated for the density and frequency you are trying to run.

Key Points on Why Not to Combine Memory Kits:

 

Mismatched Timings and Density:

    • Memory vendors bin kits at specific densities.

    • Combining kits for higher density invalidates programmed timings, leading to potential issues.

Troubleshooting Challenges:

    • If rated timings fail, returning both kits or tuning the system becomes necessary.

    • Tuning requires a deep understanding of memory timings, posing challenges and technical considerations that are difficult to simplify (to learn more, read here ).

Time-Consuming Tuning Process:

    • Tuning memory settings demands significant time, a systematic approach, and patience.

    • Lack of knowledge on memory timings complicates the tuning process.

Recommendation for Simplicity:

    • Combining kits can lead to complex memory troubleshooting.

    • Purchase a single, compatible memory kit for a smoother experience.

 

13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

Angel777
Level 8

..strange, in another of my pc z490 i mix 2+2 kits and xmp works..was I lucky? 🙂

CLAUDIOLDN
Level 7

I have struggled with xmp ever since I upgraded last year... Seems someone forgot to tell the customers that although they wasted the design of the motherboards with 4 dimm slots... Only two work without headaches on the z790... And everyone wanting to use the 4 DIMM slots would be in trouble.

Anyway I won't buy flagship motherboards anymore... Because they are just a waste of money... I hope the z790 maximus extreme lasts at least five years or I won't be buying Asus again either. 

Very disappointed with Asus intel Corsair and all this waste of my experience.

Cláudio Alves

Angel777
Level 8

so i have installed and works (from the same seller)

2x CMH32GX5M2B6400C32

2x CMH32GX5M2B6400C32W

are not compatible (in XMP)? i don't undestand why..

Technical specifications (in photo)

kit1kit1kit2kit2

 

Because it's not a 4x16 kit, you have two separate 2x16 Kits. XMP is only valid to the kit's themselves. That doesn't mean that you can't try to apply the XMP profile to 4 dimms, but odds of it working (depending on speed) could be quite low. I am honestly surprised Corsair has a 4x16 6400 kit, shoot they even sell a 6800 kit. Both those speeds can be quite a challenge to achieve with 4 dimms. If you are going to want to try to achieve 6400 you're going to need to manually tune. I wouldn't be shocked even if you purchased the 4x16 kit, XMP very well may not work.

 Is there part of my initial reply that's unclear?

See here:

Mismatched Timings and Density:

    • Memory vendors bin kits at specific densities.

    • Combining kits for higher density invalidates programmed timings, leading to potential issues.


      If the vendor is binning the kit to operate at a specifiic density and the user then adds an additional two modules, it's no longer the same density and there is no assurance in place that the memory is able to operate at the kits programmed frequency, voltage or timings.

13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

i manual changed to these settings Xmp1 (enabled) and stable /works (with games like cyberpunk and apps), so

i changed memory speed to 5800mhz, the result:

Total Size
65536 MB
Type
Quad Channel (256 bit) DDR5-SDRAM
Frequency
2892.9 MHz (DDR5-5786) - Ratio 1:29
Timings
32-40-40-84-124-2 (tCAS-tRCD-tRP-tRAS-tRC-tCR)
Slot #1 Module
Corsair 16384 MB (DDR5-4800) - XMP 3.0 - P/N: CMH32GX5M2B6400C32
Slot #2 Module
Corsair 16384 MB (DDR5-4800) - XMP 3.0 - P/N: CMH32GX5M2B6400C32
Slot #3 Module
Corsair 16384 MB (DDR5-4800) - XMP 3.0 - P/N: CMH32GX5M2B6400C32
Slot #4 Module
Corsair 16384 MB (DDR5-4800) - XMP 3.0 - P/N: CMH32GX5M2B6400C32
🙃