Short answer: for most 4TB NAS builds, buy the WD Red Plus 4TB (WD40EFZZ). It costs about $190 on Amazon right now. The Seagate IronWolf 4TB (ST4000VN008) runs about $265. Both carry the same 180TB/year workload rating and three-year warranty. Pick the IronWolf when you want its larger 256MB cache, the slightly faster 5900 RPM spindle, and Seagate's IronWolf Health tooling, and the price gap does not bother you.
WD Red Plus vs IronWolf 4TB at a glance
| Spec | WD Red Plus 4TB (WD40EFZZ) | Seagate IronWolf 4TB (ST4000VN008) |
|---|---|---|
| Recording | CMR | CMR |
| Spindle speed | 5400 RPM | 5900 RPM |
| Cache | 128MB | 256MB |
| Workload rating | 180TB/year | 180TB/year |
| Rated NAS bays | Up to 8 | 1 to 8 |
| Warranty | 3 years | 3 years |
| Recent Amazon price | about $190 | about $265 |
| Amazon rating | 4.3 | 4.4 |
| Attribute | WD Red Plus 4TB NAS Internal Hard Drive (WD40EFZZ) | IronWolf 4TB NAS Internal Hard Drive (ST4000VN008) |
|---|---|---|
| Rating | 4.3 | 4.4 |
| Price | $100-$200 | $200-$500 |
| Capacity | 4 TB | 4 TB |
| Rotational speed | 5400 RPM | 5900 RPM |
| Cache | 128 MB | 256 MB |
| Recording technology | CMR | CMR |
| Interface | SATA 6 Gb/s | SATA 6 Gb/s |
| Workload rating | 180 TB/yr | 180 TB/yr |
| Warranty | 3 years | 3 years |
| Form factor | 3.5 inch | 3.5 inch |
| Rated NAS bays | Up to 8 | 1 to 8 |
| Buy | Check price on Amazon | Check price on Amazon |
Both drives are 3.5-inch SATA, CMR NAS drives in the same mid-tier class. This is a NAS drive vs NAS drive comparison, not an SMR vs CMR explainer. If you are still working out why some cheap drives slow to a crawl during RAID rebuilds, start with SMR vs CMR Hard Drives: Why Your External Drive Slows to a Crawl. For more drive, NAS, and home server guides, see the NAS and Home Lab hub. Specs below come from manufacturer datasheets and current Amazon listings, not lab benchmarks.
Price and value
Winner: WD Red Plus 4TB. At about $190 for the WD40EFZZ and about $265 for the ST4000VN008, the gap is roughly $75 per drive. In a four-bay array that adds up to about $300 before tax. The Red Plus works out to roughly $47 per terabyte; the IronWolf is closer to $66.
Hard drive prices are elevated this fall, so check the per-terabyte math before you commit to 4TB. The WD Red Plus 8TB currently lists near $355, which is cheaper per terabyte than either 4TB drive and leaves more room for a growing Plex library. See Build a Plex Media Server: Everything You Need in 2026 for how drive size fits a full server build.
Speed, cache, and workload
Winner: IronWolf on paper, tie in practice. The IronWolf spins at 5900 RPM and carries 256MB of cache, against 5400 RPM and 128MB on the WD40EFZZ. On a gigabit network both drives can fill the link for large sequential files, so the difference mostly shows up in local copies, scrubs, and rebuild times rather than in Plex streaming or Time Machine backups.
Both list a 180TB/year workload rating. That is plenty for media libraries, photo archives, and backup targets. If you plan heavy surveillance recording or always-on virtual machine disks, step up to IronWolf Pro or WD Red Pro instead.
Warranty and data recovery
Winner: tie. Both ship with a three-year limited warranty. Seagate bundles Rescue Data Recovery with some IronWolf SKUs; confirm on the listing whether the unit in your cart includes it before you count on it. Neither warranty replaces backups. If a drive does fail, our guide to replacing a failed RAID drive walks through the swap.
Noise and heat
Winner: WD Red Plus, slightly. The lower 5400 RPM spindle tends to run a little cooler and quieter than a 5900 RPM drive, which matters in a bedroom or living room NAS. In practice, case fans and vibration damping make a bigger difference than the drive brand. Leave airflow clear and avoid packing warm drives into a sealed desktop case.
Who each drive fits
Buy the WD Red Plus 4TB if you want the lowest cost CMR NAS drive, you are filling a home NAS of up to eight bays, and you keep separate backups.
Buy the Seagate IronWolf 4TB if you want the bigger cache and faster spindle, you already standardize on IronWolf, or a sale flips the price gap in its favor.
Skip both if you need more than 180TB/year of writes, want 7200 RPM performance, or only need a single USB backup drive. Not sure which array layout to use? Read RAID Levels Explained: Which One Your NAS Should Use first.
Bottom line
The WD Red Plus 4TB (WD40EFZZ) is the better buy for most people right now: same CMR class, same workload rating, same warranty, and about $75 less per drive. The IronWolf 4TB (ST4000VN008) is the pick when 256MB cache and 5900 RPM matter to you. Either way, buy matched drives for one array and View on Amazon for today's price before you order a full set.
