ECC DDR5-4800 vs. DDR5-5200 Memory Performance For AMD Ryzen Zen 4
Back when looking at the AMD Ryzen 7000 series budget server performance last year, DDR5-4800 ECC UDIMMs were used with the ASRock Rack 1U4LW-B650/2L2T Ryzen server given that's what was broadly available at the time. Since then there's been more ECC UDIMMs coming to market above DDR5-4800 speeds. Recently I bought a pair of Kingston Server Premier 32GB 5600MT/s DDR5 ECC CL46 UDIMMs (KSM56E46BD8KM-32HA) and that's the focus of today's tests. For those curious if the faster ECC UDIMMs are worthwhile compared to the commonality of DDR5-4800 ECC UDIMMs, these benchmarks are for you.
The Kingston Server Premier 32GB 5600MT/s KSM56E46BD8KM-32HA ECC Unbuffered DIMMs have a CAS latency of 46 and rated for DDR5-5600 speeds. However, the AMD Ryzen 7000 series processors are only able to run the ECC UDIMMs up to DDR5-5200 speeds. I ended up buying the KSM56E46BD8KM-32HA for later upgradeability and for not being able to find any DDR5-5200 ECC UDIMMs in stock at the time... Micron listings for their DDR5-5200 ECC UDIMMs ended up being all out-of-stock. Kingston offers these DDR5 ECC UDIMMs also in 16GB and 48GB varieties for those interested.
For this testing it's quite a straight-forward comparison looking at the DDR5-4800 vs. DDR5-5200 performance with an AMD Ryzen 9 7900 processor running with the ASRock Rack 1U4LW-B650/2L2T 1U server platform. The ASRock Rack 1U4LW-B650/2L2T with B650D4U-2L2T motherboard continues working quite well as an AMD Ryzen 7000 series server motherboard and hasn't had any issues with these 2 x 32GB KSM56E46BD8KM-32HA UDIMMs or the dual Micron MTC20C2085S1EC48BA1 32GB DDR5-4800 memory originally bought for this platform. Memory timings were at their default programmed values.
These benchmarks were carried out on Ubuntu 24.04 LTS with the Linux 6.8 kernel. Again these performance benchmarks are primarily intended for information purposes for those deciding whether to go for DDR5-4800 ECC UDIMMs given their commonality and more robust availability versus DDR5-5200 (or DDR5-5600) ECC UDIMs for better performance and at a slight performance benefit but as of writing seem to still have limited availability from various Internet retailers.