DDR5-6400 vs. DDR5-4800 R-DIMM Performance For Threadripper 9980X / 9970X CPUs

Written by Michael Larabel in Memory on 8 August 2025 at 10:40 AM EDT. Page 2 of 9. 19 Comments.

👁 Timed Linux Kernel Compilation benchmark with settings of Build: defconfig. Threadripper 9980X was the fastest.

👁 Timed Linux Kernel Compilation benchmark with settings of Build: allmodconfig. Threadripper 9980X was the fastest.

In the case of compiling the Linux kernel, there were slight benefits to the build speed here running at DDR5-6400 rather than DDR5-4800 on the Threadripper 9000 series.

👁 Timed LLVM Compilation benchmark with settings of Build System: Ninja. Threadripper 9980X was the fastest.

👁 Timed LLVM Compilation benchmark with settings of Build System: Unix Makefiles. Threadripper 9980X was the fastest.

When it came to compiling the LLVM compiler stack there was a much more pronounced benefit from the faster memory. Saving 10~12 seconds per build of LLVM by using DDR5-6400 rather than DDR5-4800. But these new Zen 5 Threadripper CPUs even with DDR5-4800 memory were still showing solid gains over the Threadripper 7000 series with the same DDR5-4800 configuration.

👁 Timed Godot Game Engine Compilation benchmark with settings of Time To Compile. Threadripper 9980X was the fastest.

👁 Timed Gem5 Compilation benchmark with settings of Time To Compile. Threadripper 9980X was the fastest.

👁 Build2 benchmark with settings of Time To Compile. Threadripper 9980X was the fastest.

👁 Timed Eigen Compilation benchmark with settings of Time To Compile. Threadripper 9980X was the fastest.

It depended upon a lot on the particular codebase with the number of source files and other factors but the benefit varied for how much DDR5-6400 helped the compile times with the Threadripper 9000 series.

👁 LocalScore benchmark with settings of Model: Llama-3.2-1B-Instruct-Q4_K_M.gguf, Acceleration: CPU. Threadripper 9970X was the fastest.

👁 LocalScore benchmark with settings of Model: Llama-3.2-1B-Instruct-Q4_K_M.gguf, Acceleration: CPU. Threadripper 9980X was the fastest.

👁 LocalScore benchmark with settings of Model: Meta-Llama-3.1-8B-Instruct-Q4_K_M.gguf, Acceleration: CPU. Threadripper 9980X was the fastest.

👁 LocalScore benchmark with settings of Model: Meta-Llama-3.1-8B-Instruct-Q4_K_M.gguf, Acceleration: CPU. Threadripper 9970X was the fastest.

👁 LocalScore benchmark with settings of Model: Qwen2.5-14B-Instruct-Q4_K_M.gguf, Acceleration: CPU. Threadripper 9980X was the fastest.

👁 LocalScore benchmark with settings of Model: Qwen3-32B-Q4_K_M.gguf, Acceleration: CPU. Threadripper 9980X was the fastest.

Meanwhile for those doing CPU-based AI inferencing with AMD Threadripper, the DDR5-6400 memory is definitely worthwhile to upgrade from DDR5-4800 for peak performance. No real surprise here but useful to quantify the performance difference.

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URL: https://www.phoronix.com/review/threadripper-9000-ddr5-6400-4800/2

⇱ DDR5-6400 vs. DDR5-4800 R-DIMM Performance For Threadripper 9980X / 9970X CPUs - Phoronix

DDR5-6400 vs. DDR5-4800 R-DIMM Performance For Threadripper 9980X / 9970X CPUs