MRDIMM 8800MT/s vs. DDR5-6400 Memory Performance With Intel Xeon 6

Last week when kicking off the Intel Granite Rapids benchmarking with the Xeon 6980P processors there was particularly strong performance within HPC and other scientific computing workloads. Besides going now up to 128 cores / 256 threads per socket, another reason for the especially strong generational uplift and against the current AMD EPYC competition is Xeon 6 Granite Rapids introducing Multiplexed Rank memory support. One of the areas I've been eager to explore is quantifying the DDR5-6400 vs. MRDIMM 8800MT/s performance difference and this article is dedicated to looking at that memory performance impact for the Xeon 6900P series.