Hard Disk Prices
← Live table

SSD vs HDD for a NAS: Why Hard Drives Still Win at Home

Updated

For most home NAS boxes on gigabit networking, hard drives are the right bulk storage: the network caps transfers around 116 to 118 MB/s, one NAS hard drive can outrun that, and SSDs cost far more per TB. Use SSDs as cache, or all-flash with 10GbE.

SSD vs HDD for a NAS: the short answer

For most home NAS setups, hard drives are the right choice for bulk storage, for two reasons: on a typical gigabit (1GbE) network the network itself is the bottleneck, and hard drives cost far less per terabyte than SSDs.

SSDs still earn a place in a NAS. They work well as cache for random, small-block workloads like virtual machines and databases, and an all-flash NAS makes sense with 10GbE networking and workloads that need the speed.

Your network is usually the bottleneck

Gigabit Ethernet is the most common connection on home NAS boxes. It tops out at 125 MB/s in theory and about 116 to 118 MB/s in practice after protocol overhead, according to NetApp's knowledge base. That is the ceiling for any transfer over the network, however fast the drives behind it are.

A single modern NAS hard drive is rated faster than that link: Seagate rates its IronWolf and IronWolf Pro drives, and Toshiba its N300 drives, at roughly 210 to 298 MB/s maximum sustained transfer. So on 1GbE, swapping hard drives for SSDs buys little for large file transfers.

Cost per TB

Hard drives cost far less per terabyte than SSDs, and in the data center the gap has widened: Tom's Hardware, citing the VDURA index, reported data-center SSDs at about 18.6 times the cost per TB of hard drives in Q3 2026, up from roughly 4.5 to 6 times a year earlier. VDURA sells hybrid flash-and-disk systems, and its index covers data-center drives rather than consumer ones.

The gap matters most when you're buying 12TB, 16TB, 20TB, or 24TB of capacity per bay. Compare current prices on the NAS hard drive and internal SSD deal pages before you decide.

Where SSDs help: cache and random I/O

SSD cache speeds up random, small-block work: file sharing with many small files, iSCSI, virtual machines, databases, and mail. Synology's SSD cache white paper describes two modes — read-only cache needs one SSD, and read-write cache needs at least two SSDs mirrored in RAID 1 — and reports up to 30 times faster random reads with cache in its tests.

Cache does little for sequential work. Streaming HD video, recording surveillance footage, and large file copies are sequential, so if your NAS mostly streams media and stores backups, the money is better spent on more hard drive capacity.

All-flash NAS: when it makes sense

An all-flash NAS makes sense with fast networking (10GbE or better) and workloads that lean on random I/O: several virtual machines, databases, or many simultaneous users. On a 10GbE link, a single hard drive becomes the bottleneck and SSDs can show their speed.

If you go all-flash, check endurance ratings: Seagate rates its NAS-oriented IronWolf 125 SSDs from 300 TBW for the 250GB model up to 5,600 TBW for the 4TB model. Be careful with QLC flash — Synology's tests found QLC SSDs can write sequentially slower than hard drives once their fast cache fills.

Power and noise

SSDs draw less power and make no noise. By Seagate's rated figures, an 8TB IronWolf hard drive draws about 9 W operating and 7.2 W idle, and a 24TB IronWolf Pro 7.8 W operating and 6.3 W idle, at 20 dBA idle and 26 dBA while seeking. An IronWolf 125 SSD draws about 2.3 to 2.8 W active and close to 0.1 W idle. At idle around the clock, that gap works out to roughly 55 to 62 kWh a year per drive.

A sensible setup

For most home NAS users, the right answer is hard drives sized to your needs, with SSD cache only if you run random-I/O workloads. Buy CMR drives — the CMR vs SMR explainer covers why — and consider upgrading your network before your drives.

FAQ

Is it worth putting SSDs in a NAS?

For specific workloads. SSD cache helps random, small-block tasks like virtual machines, databases, and shares with many small files — Synology measured up to 30 times faster random reads. For bulk storage on gigabit networking, hard drives are the better buy: the network is the bottleneck and SSDs cost far more per TB.

Do I need an SSD cache for Plex or media streaming?

No. Media streaming is sequential, and SSD cache helps random, small-block I/O instead. Synology's SSD cache white paper says cache doesn't improve sequential work like HD video streaming or surveillance recording, so spend that budget on more hard drive capacity.

Will SSDs make my NAS faster on a gigabit network?

Not for large transfers. Gigabit Ethernet delivers about 116 to 118 MB/s in practice, while one modern NAS hard drive is rated for 210 to 298 MB/s sustained, so the network is the limit. SSDs can still help random, small-file work, but for big copies upgrade to 2.5GbE or 10GbE first.

Can I mix SSDs and hard drives in a NAS?

Yes. The common setup is hard drives for bulk storage plus SSDs as cache — one SSD for read-only cache, or two mirrored in RAID 1 for read-write cache, per Synology. A full all-flash build makes sense only with fast networking and random-I/O workloads.

Sources