AMD EPYC ram choice
AMD EPYC ram choice
Gday all, trying to figure out the best memory setup for my EPYC CPU setup. I'm replacing my Ryzen 1700 with an EPYC and need enough RAM for unraid. I have a few choices: 8 sticks of 8GB at 2133mhz or 4 sticks of 16GB at 3200mhz. Prices are similar, and I don’t expect to need more than 64GB in the future. Since EPYC uses eight channels, I’m leaning toward 8x8 for better bandwidth. On the other hand, 4x16 gives higher throughput per stick. My needs lean more toward hosting virtual machines with GPU passthrough and some headless servers like Factorio or Minecraft. So, comparing equal amounts of memory—4x3200mhz versus 8x2133mhz—what’s the better option?
I'm searching for details about CAS/CL settings for the EPYC 7003 processor line. This article appears relevant as others may be viewing it when looking up similar topics. The AMD EPYC RAM recommendations emphasize filling all eight channels to get optimal memory bandwidth. Using 8x L/RDIMMs is advised, with a suggested clock speed of around 2,933 MHz. While other configurations exist—such as 4x DIMMs at 3,200 MHz—they offer lower speeds. I’m curious if motherboard support varies for these lower clock rates. In theory, achieving higher clock speeds could influence core performance, similar to Ryzens’ approach. To compare transfer speeds, refer to the attached spreadsheet; it helps visualize differences. Keep in mind that RAM speed isn’t just about clock rate but also how quickly data cycles occur, which can affect overall efficiency. Additional timing factors beyond CAS/CL are needed for precise calculations, but this should give a clearer picture. The document also notes that running with only 4x DIMMs might boost bandwidth but adds a small latency penalty if you go to 8x. For EPYC 7003 models, supported RAM speeds generally cap around 3,200 and 2,933 MHz, though newer releases may push higher. If you need faster access, consider the trade-offs between speed and stability.