RogStrix B650E-E Gaming wifi Ram Problem

[3DLands]

I paired this mainboard with a Ryzen 9 7950x and 128 GB Ram DDR5 5600 Kingston cod: KF556C40BBK2-64
I obviously checked first on the data sheet of the Asus site and the Ram is supported.
The problem is that with two modules (2x32) leaving everything in auto, the ram is seen and recognized as 4800Mhz, even windows recognizes it as 4800Mhz. By also installing the other two modules for a total of 128Gb, the mainboard sees them, everything works and is stable, however everything is at 3600.
Trying to activate any profile to force the ram to its frequency of 5600 everything becomes unstable and can't even boot.

I tried another combination of ram from Crucial but that also worked the same trick. With two banks (2x32) the ram ran at 4800 with 4 banks (4x32) always at 3600. Also with the other bank it is impossible to activate any profile due to system instability. For the bios I tried them all.

Waiting for updates from Asus....

[Murph_9000]

There are a couple of things going on here.  Firstly, the default speed of your RAM at 4800 MT/s is the rated speed of the silicon on your DIMMs.  5600 MT/s is an overclocked rating (all XMP/DOCP/EXPO memory is overclocked when running faster than the default (JEDEC) speed), so it only tries to run that speed if you enable the overclocking.

Kingston KF556C40BBK2-64 is listed on the memory QVL, but only as a 1 or 2 DIMM config (that's the "socket support" column, which would be "1,2,4" for 4 DIMM configs).  There are currently no 4 DIMM configs on the QVL for the Strix B650E-E.

As was the case with DDR4, you can't have both speed and capacity for DDR5 memory, but it's more difficult to run 4 DIMM configs with DDR5.  4 DIMM DDR5 configs are generally problematic at the moment.  This is something that might improve in the future, as DDR5 matures, but it's unlikely to ever hit the highest speeds in 4 DIMM configs.

[3DLands]

Thanks Murph_9000 for your reply.

So... what I have to do to have my 128Gb of ram declared in the motherboard specifications?? 

What type of memory is supported to reach 128Gb? What brand and model?

Isn't important for me oveclocking the system, 4800 it's OK. I use the workstation for 3D modelling and rendering 

And finally, now everything is running at 3600 without problems, is this the only way to get 128Gb?

[Murph_9000]

You could try updating to the latest BIOS, if you've not already done that, see if that helps.  Some of the memory speed and stability comes from BIOS improvements, but some of the limits for 128GB are from the CPU's memory controller and the silicon on the DIMMs (i.e. stuff the BIOS can't do much about).

Running at 3600 and being stable may be the best answer for you for now, if you really need 128GB.  There are 48GB DIMMs newly on the market (not currently on the QVL for your board), which you could potentially use to get a faster 96GB config (or 192GB slower config).  As far as I know, running at 3600 with 4 DIMMs comes from AMD, as their default 4 DIMMs with no overclocking.  It's possible that you might be able to manually overclock a little bit and push it up to maybe 4000 or 4400.