Best 4TB NAS Drive in 2026: 3 CMR Drives Compared

The 4TB tier makes sense when you’re filling a NAS on a tight budget, replacing a single failed drive, or building a small mirror where redundancy matters more than raw capacity. Price per terabyte varies by capacity, so compare current offers with the 8TB tier before you commit.

All three drives here are CMR (Conventional Magnetic Recording), according to their datasheets. SMR drives slow down badly during RAID rebuilds and long writes; for the full breakdown, see our CMR vs SMR guide. The product cards above list each drive’s full specs.

Our Pick: Seagate IronWolf 4TB

The Seagate IronWolf 4TB (ST4000VN006) is the safest all-round choice at 4TB.

• 5,400 RPM, 256 MB cache, CMR
• 202 MB/s maximum sustained transfer
• 180 TB/year workload rating, 1 million hours MTBF
• 3.2 W idle, 3.7 W average operating; 23 dBA idle, 25 dBA seek (Seagate ratings)
• 3-year warranty plus three years of Rescue Data Recovery

Seagate lists RV sensors on the 4TB model and rates it for NAS systems with 1 to 8 bays. IronWolf Health Management adds drive-health recommendations on supported NAS systems (confirm support with your NAS vendor). AgileArray firmware provides dual-plane balancing and time-limited error recovery, which limits how long the drive retries a bad sector so a RAID array is less likely to drop it.

Rescue Data Recovery covers Seagate’s in-lab recovery service for three years where the service is offered. Treat it as insurance, not a backup.

At 202 MB/s, the IronWolf outruns a 1GbE link, which carries at most 125 MB/s before protocol overhead. If you have 2.5GbE or faster networking, the Toshiba N300 is rated faster.

WD Alternative: WD Red Plus 4TB

The WD Red Plus 4TB (WD40EFPX) is a solid CMR NAS drive, but the IronWolf 4TB has a higher transfer rating and more NAS features.

• 5,400 RPM, 256 MB cache, CMR
• 180 MB/s transfer rating
• 180 TB/year workload rating, 1 million hours MTBF
• 3.1 W idle, 4.7 W read/write; 23 dBA idle, 27 dBA seek (WD ratings)
• 3-year warranty

The critical detail: buy the Red Plus (WD40EFPX), not the plain WD Red WD40EFAX, which WD lists as SMR. WD’s current Red Plus datasheet lists every Red Plus model as CMR. For more on WD’s naming, see IronWolf vs WD Red Plus.

WD tunes the Red Plus with NASware firmware and dual-plane balance control, and rates it for NAS systems with up to 8 bays, but it does not list RV sensors. There is no bundled recovery service and no IronWolf Health Management. Choose it when it costs less than the IronWolf when you buy, or when you want matching WD drives for an existing array.

Fastest: Toshiba N300 4TB

The Toshiba N300 4TB is the performance option, with a 7,200 RPM spindle and the highest transfer rating here.

• Model HDWG440: 7,200 RPM, 256 MiB buffer, CMR
• 232 MB/s sustained transfer (Toshiba rating)
• 180 TB/year workload rating, 1 million hours MTTF
• 4.0 W active idle, 6.8 W operating
• 3-year warranty

That rating is about 15% above the IronWolf’s 202 MB/s. You will see the difference only on 2.5GbE or faster networks moving large files; over 1GbE, the network is the limit. Toshiba builds in RV sensors, as Seagate does.

The trade-offs are power and extras. The N300 draws the most power of the three: at $0.18 per kWh, its 0.8 W higher idle draw than the IronWolf costs about $1.30 per drive per year. There is no bundled recovery service or IronWolf-style health integration.

Buying Criteria: What to Look for in a 4TB NAS Drive

CMR vs SMR Recording

This is the single most important spec. CMR writes tracks side by side without overlap. SMR overlaps tracks to fit more data, so the drive must rewrite whole bands to change a small piece of data, which hurts sustained writes and RAID rebuilds. Every drive on this page is CMR. Full details are in our CMR vs SMR guide.

Workload Rating

All three drives are rated for 180 TB/year, about 490 GB per day of reads and writes combined. A home NAS serving media, nightly backups and file shares rarely approaches that; continuous surveillance recording or a busy multi-user backup target might. For most home lab NAS builds, 180 TB/year is plenty.

RPM and Sequential Throughput

Seagate rates the IronWolf 4TB at 202 MB/s, WD rates the Red Plus 4TB at 180 MB/s, and Toshiba rates the N300 4TB at 232 MB/s. Over 1GbE, all three saturate the link. On 2.5GbE (312.5 MB/s), the N300’s higher rating can help with large sequential transfers.

Cache Size

All three list 256 MB of cache (Toshiba states 256 MiB). Cache mostly helps bursts of small random reads and writes rather than long sequential transfers.

Warranty and Data Recovery

Seagate includes three years of Rescue Data Recovery with the IronWolf. WD and Toshiba offer standard 3-year warranties without a recovery service. If your backups are solid, Rescue is a nice extra rather than a must-have.

RV Sensors

Seagate lists RV sensors on the IronWolf 4TB, and Toshiba builds them into the N300. WD does not list them for the Red Plus. They matter more as the number of drives in a chassis rises, so for a 5-bay or larger NAS, stick with the IronWolf or N300.

How to Choose

Most builds, including Synology and QNAP: Buy the Seagate IronWolf 4TB. RV sensors, low power, IronWolf Health Management and Rescue make it the most complete option.

Fastest transfers on 2.5GbE or faster: Buy the Toshiba N300 4TB for its 232 MB/s rating, if you can accept higher power draw and no extras.

Matching an existing WD array, or a better price on the day: Buy the WD Red Plus 4TB, and confirm the model is WD40EFPX.

Bottom Line

The Seagate IronWolf 4TB is the best 4TB NAS drive for most home lab builders: RV sensors, a 202 MB/s rating, low power, IronWolf Health Management and Rescue data recovery. The Toshiba N300 4TB is the fastest-rated option. The WD Red Plus 4TB is a solid alternative when it costs less or you want to match WD drives.

All three are CMR, all three are designed for 24/7 operation, and all three carry 3-year warranties.

For a broader look at NAS drives across all capacities, see our complete NAS drive guide. For NAS hardware to put these drives in, see best NAS for home lab.