DDR5 Memory Channel Scaling Performance With AMD EPYC 9004 Series

The WRF weather forecasting software certainly could make use of all twelve memory channels with the AMD EPYC 9004 series, but if your budget is constrained, running with ten DIMMs per socket may prove to be the best bang for your buck.

The Blender 3.4 rendering performance with larger scenes like Classroom and Barbershop weren't seeing any measurable difference from six to twelve channels with the EPYC 9654 processors.

Hopefully this reference data was of some help if curious over the benefits or independent justification of twelve DDR5 memory channels available with AMD EPYC 9004 "Genoa" processors. Those interested in even more data from various different workloads can find 130+ different benchmark results from this 6/8/10/12 memory channel comparison here with the EPYC 9654 2P setup.

When taking the geometric mean just for the workloads able to effectively leverage going from 6 to 12 memory channels, here is how that compares. Going from six to eight channels and eight to ten channels at each step was a 16~20% improvement in performance but going from ten to twelve channels it narrowed to a 10% improvement. If not needing to maximize your addressable RAM capacity and looking to shave off some costs to an EPYC 9004 series upgrade (or at least shifting some additional costs for another quarter or once DDR5 server memory prices have dropped), running at 10 DIMMs per socket would provide slightly better value for a number of the workloads tested while not losing too much performance. For workloads like WRF, OpenFOAM, nekRS, and select AI workloads depending upon the model, going for twelve DDR5-4800 memory channels is certainly worthwhile with the AMD EPYC 9004 series processors for achieving peak performance.