Best used server for a NAS or Plex box (2026)
A NAS or Plex box is the most always-on server most people own, so the math is different from a lab box you boot occasionally: drive bays and idle power matter more than raw CPU. Here's how to choose, and what to ignore.
What actually matters for a NAS/Plex server
Drive bays first
Count the bays you need plus headroom (3.5" LFF for bulk storage, 2.5"/NVMe for cache). A 12-bay LFF chassis is the storage workhorse. Filter to the NAS lens, which ranks on bays + power + value.
Idle power (this is the cost)
On 24/7, idle watts are the real bill: 60 W vs 150 W is roughly a $120/year difference at $0.15/kWh. Every listing shows its idle-power figure - favor the low end; see the quiet & low-power reference.
Plex transcoding
For Plex, an iGPU/QuickSync (or a cheap GPU) handles hardware transcoding far more efficiently than CPU transcoding on an old Xeon. If you'll transcode, weigh a newer low-power box over a many-core old one - fewer watts per stream.
Noise, if it lives with you
A NAS often sits in an office or closet - check the noise tier. A tier-4/5 datacenter box is miserable nearby; a quiet box is worth a small premium for an always-on unit.
Pitfalls
- Buying CPU you won't use. A NAS rarely needs 40 cores; spend on bays and low power, not a dual-socket monster that idles high.
- Ignoring the backplane/caddies. Confirm the bays come with caddies and the backplane matches your drives (SAS/SATA); "no caddies" adds cost.
- Drives sold as RAM / mis-specced storage. We parse drive bays and capacity from the listing, but verify the seller's photos for a storage box.
- Loud + thirsty "deals." The sticker may be low, but a 150 W tier-5 box is the wrong NAS - our score surfaces power and noise so you see the real trade-off.