Failing to reach DDR4 bandwidth
You are missing one critical element: NUMA awareness.<p>Because of the Chiplet design, Threadrippers and EPYC chips are basically NUMA systems, like you would with a multi-socket motherboard. This has an impact on both memory latency and bandwidth.<p>Redo your test, but pin each thread to a CPU thread, and its memory pool to a stick of ram attached directly to the CCX of said thread. The bandwidth you are measuring is the Infinity Fabric&#x27;s bandwidth, NOT the DDR4 bandwidth.<p>You can read more about infinity fabric and its bandwidth here: <a href="https:&#x2F;&#x2F;en.wikichip.org&#x2F;wiki&#x2F;amd&#x2F;infinity_fabric" rel="nofollow">https:&#x2F;&#x2F;en.wikichip.org&#x2F;wiki&#x2F;amd&#x2F;infinity_fabric</a>