DDR5 ECC vs DDR4 ECC: What Actually Changes for Server Workloads?
Moving from DDR4 ECC to DDR5 ECC isn't just a version bump. DDR5 changes the memory architecture itself.
Key differences
Speed: DDR4 runs at 1600–3200 MT/s. DDR5 starts at 4800 MT/s.
Bandwidth (theoretical, per channel): 25.6 GB/s (DDR4-3200) vs 38.4 GB/s (DDR5-4800)
On-Die ECC: DDR5 corrects certain errors inside the DRAM chip. This is not a replacement for system-level ECC.
Architecture: two 32-bit subchannels, burst length 16, and 32 banks (vs 16)
Power and density: about 1.1V vs 1.2V, with higher-density modules
Compatibility: DDR4 and DDR5 cannot be mixed. You need a new platform.
Which should you choose?
DDR4 ECC works well if you already have a DDR4 platform and your workload doesn't need more bandwidth or capacity.
DDR5 ECC fits new builds, bandwidth-intensive workloads, big-RAM virtualization, and high-core-count CPUs.
📖 Read more: https://www.fitservers.com/blogs/ddr5-ecc-vs-ddr4-ecc-server-workloads/
El dato de los dos subcanales de 32 bits en DDR5 es el que realmente cambia el juego, no es lo mismo que el bus único de DDR4. Ojo que el On-Die ECC ese no reemplaza al ECC del sistema, mucha gente lo confunde. Para virtualización pesada con muchos cores, la diferencia en bandwidth se nota.