AMD Ryzen 9 9950X DDR5-6000 / DDR5-6400 / DDR5-8000 Memory Performance
The Leela Chess Zero deep neural network chess software had troubles running with the 2 x 24GB DDR5-8000 Corsair CMP48GX5M2X8000C38 memory kit while the other DDR5-8000 kit worked without issues on this Ryzen 9 9950X Linux desktop.
Switching over to the Eigen back-end for Leela Chess Zero, all four memory kits were working fine with the CMH32GX5M2X8000C36 kit yielding the best performance.
In the Quicksilver benchmark for a simplified dynamic Monte Carlo particle transport problem, the DDR5-6400 memory kit was yielding similar uplift to the DDR5-8000 memory kits.
The Corsair 2 x 32GB DDR5-6400 CL32 CMK64GX5M2B6400C32 kit was commonly performing similar to the DDR5-8000 memory at CL38 while costing much less. If you don't already own DDR5-6000+ memory you are wanting to re-use with a Ryzen 9000 series system, going for DDR5-6400 certainly is looking good in many workloads.
The Corsair CMP48GX5M2X8000C38 kit was unable to successfully run the OpenFOAM CFD software as it would eventually yield segmentation faults although the other kits worked fine.
That DDR5-8000 CMP48GX5M2X8000C38 kit on the Ryzen 9 9950X desktop was also running into similar problems with some of the Altair OpenRadioss tests.