Question Add a second kit of Kingston Fury Renegade RGB 6400 CL2 DDR5 memories with problems (blue screen ,etc...)

[fesg]

After spending 2 months with the new PC and Kingston Fury Renegade RGB 6400 CL2 DDR5 memories and everything was perfect, depending on which tasks it fell short, so I decided to add a second kit of the same type to have a total of 64 GB.

System:
ASUS ASUS ROG MAXIMUS Z790 HERO
Core i9 13900K (for all that is still tested without any OC outside the normal "factory" state of the motherboard)
Custom liquid cooling, with EKW and EK-Quantum Velocity 2 D-RGB water block for 1700
Corsair RM1000i
Kingston Fury Renegade DDR5 RGB 6400 Mhz CL32
Samsung 990PRO 1TB
MSI Suprim X RTX 3080 Ti
Windows 11 PRO

To get to the exposed problem I tried many things, including clear bios and putting the four modules in their respective slots so that each pair goes in its alternate place.
The problem arises already when starting with the XPM profiles. It takes a long time for the bios to start up, I see the codes that are passing and all those who take their time mention memory.

With windows running, everything is Ok until it fails and blue screens appear, searching the internet for everything related to memory.
I try the memory without the XMP profiles and there is no problem, except that we are at 4800 Mhz and I have bought 6400 Mhz memory and Cl 32 which is not cheap.
Putting the memory at 6000 Mhz in one of the XMP profiles, and raising the voltage very little over what the profile marks, I get much more stability, but not total as with a single module that is absolute.

GENERAL QUESTION: I know that DDR5 is... special (very badass). Is it incompatible to add a second module all with XMP and within its specifications? Going from 6400 to 6000 is a lesser evil as the system is insanely fast, but it SHORTS me that I paid for something I can't use. Or should everything work OK and there is a problem with the memories too optimistic to work 4 modules together at 6400 Mhz? Kingston does not indicate that this combination is incorrect... And at the moment it is not completely stable at 6000 Mhz...

 

[ex_bubblehead]

You should always use matched sets (XXGB x 2 or x 4) Using unmatched sets almost always leads to what you are experiencing. Just because 2 packages have the same part number does not make them matched. Only if they are packaged together, in the same physical package are they matched.

 

[fesg]

You should always use matched sets (XXGB x 2 or x 4) Using unmatched sets almost always leads to what you are experiencing. Just because 2 packages have the same part number does not make them matched. Only if they are packaged together, in the same physical package are they matched.

Yes, it is true as you say.
There's a clear clue on Kingston's own page. For 64 GB, there are only 2 modules (2x32GB) and at 6000 Mhz. There is no 64GB version with 6400 Mhz.
It's nothing serious. If the voltage is increased (the base XMP profile is for 1.4v and I am still at about 1.38v with 6000 Mhz. There is room and I think they end up stable. What I need is 64GB, and 6000 Mhz is already quite good.