HDD vs SSD for NAS

For most builds, HDDs for the data pool and one or two SSDs as cache. HDDs deliver several times more storage per dollar, which is decisive for bulk media, backups, and file shares; SSDs earn their place for high-IOPS tiers (VMs, databases, Docker) or all-flash pools. A hybrid HDD-pool-plus-SSD-cache setup is the most cost-effective for typical home and small-office NAS. The table on this page prices both against today’s listings.

Only where IOPS matter. A 4-bay NAS with 16 TB HDDs gives 64 TB raw; the same bays with 4 TB SSDs give just 16 TB, at far higher cost. Most NAS workloads are sequential and limited by the network, not the drives, so all-flash pays off mainly for VM storage, databases, or metadata-heavy workloads — not for a media server.

Usually not for file serving, because the network is the bottleneck. A 1 GbE NAS maxes out around 110 MB/s — a single HDD can already saturate that. Even 2.5 GbE (280 MB/s) is within reach of an HDD array. You need 10 GbE before SSD speeds actually show up in NAS file transfers; below that, SSDs add cost without throughput.

Yes, modestly. A NAS HDD draws about 5–8W under load versus 2–3W for a SATA SSD. Across 4–8 drives running 24/7 that is roughly $20–60/year more in electricity — worth noting for an always-on build, but small next to the several-fold capacity cost advantage HDDs hold.

HDDs spin, so they generate audible noise (about 25–35 dBA) and vibration, which is more noticeable in multi-bay enclosures. SSDs are silent with zero vibration. If your NAS lives in a bedroom or living room, that is a real quality-of-life factor — one reason some people accept the cost of a hybrid or all-flash build.