Shopping for a 4TB drive to drop into a home or small-office NAS is mostly a brand choice now. The WD Red Plus 4TB (WD40EFPX) and the Seagate IronWolf 4TB (ST4000VN006) sit in the same class: 3.5-inch SATA, CMR recording, 256MB cache on the current sheets, a 5400 RPM class spindle, and a 180TB/year workload rating aimed at multi-bay NAS chassis.
This is a NAS-drive vs NAS-drive comparison, not an SMR vs CMR explainer. Both of these 4TB models are CMR. If you are still sorting why some cheaper "NAS" or desktop drives slow down under RAID rebuilds, start with /wiki/cmr, /wiki/smr, and SMR vs CMR Hard Drives: Why Your Drive Slows Down. Specs below come from manufacturer datasheets and current Amazon listings. No fake.
| Attribute | WD Red Plus 4TB NAS Internal Hard Drive, CMR (WD40EFPX) | Seagate IronWolf 4TB NAS Internal Hard Drive (ST4000VN006) |
|---|---|---|
| Rating | 4.6 | 4.5 |
| Price | $99.99 | $129.99 |
| Recording technology | CMR | CMR |
| Capacity | 4TB | 4 TB |
| Interface | SATA 6Gb/s | SATA 6 Gb/s |
| Cache | 256MB | 256 MB (Seagate spec sheet; some Amazon listings show 64 MB) |
| Spindle speed | 5,400 RPM class | — |
| Workload rate | 180TB/year | — |
| Rated bays | Up to 8-bay NAS | — |
| Warranty | 3 years | 3 years + 3 years Rescue data recovery |
| Rotational speed | — | 5400 RPM |
| Workload rating | — | 180 TB/yr |
| Form factor | — | 3.5 inch |
| MTBF | — | 1,000,000 hours |
| Buy | View on Amazon | View on Amazon |
Quick verdict
Most people filling a 4-bay or 8-bay NAS with 4TB CMR drives should buy the WD Red Plus 4TB. Street price is usually lower for the same CMR media class, 256MB cache, and 180TB/year workload rating, so the Red Plus wins on dollars per terabyte for a matched set. Pick the Seagate IronWolf 4TB when Seagate's included Rescue Data Recovery window matters more than the typical price gap, or when you already standardize on IronWolf across the chassis for firmware and support familiarity.
Price and value
Winner: WD Red Plus 4TB. Recent street pricing puts the Red Plus near $100 and the IronWolf nearer $130 for the same 4TB capacity. Both are CMR, both advertise 180TB/year, and both are sold as NAS-optimized 3.5-inch SATA drives. At roughly a $30 gap on a single drive, a four-drive RAID set swings about $120 toward WD before you count taxes or lightning deals. If your checklist is "four matched CMR 4TB NAS drives under a sane budget," Red Plus is the value default.
Workload rating, cache, and bay limits
Winner: tie on the headline class. Both drives list a 180TB/year workload rating, SATA 6Gb/s, and 256MB cache on current manufacturer sheets (some older IronWolf 4TB listing copy still shows 64MB; confirm the ST4000VN006 sheet for the SKU in your cart). WD rates Red Plus for systems up to 8 bays. IronWolf's 4TB model is likewise aimed at small multi-bay NAS use rather than enterprise JBOD farms. Neither drive is an SMR desktop rebadge in this capacity: they are the CMR NAS mid-tier, not the cheaper Red / Barracuda consumer lines.
For continuous Plex libraries, Time Machine targets, and light photo archives, 180TB/year is generous. If you are planning heavy all-day surveillance write streams or always-on virtualization disks, step up to higher-workload IronWolf Pro / Red Pro class drives instead of stretching either of these 4TB models.
Warranty and Rescue Data Recovery
Winner: Seagate IronWolf for recovery; tie on base warranty years. Both ship with a 3-year limited warranty. IronWolf's practical edge is Rescue Data Recovery Services bundled for three years on eligible IronWolf SKUs: if the drive fails in a way that leaves data on the platters, Seagate's recovery service is part of the product story in a way WD Red Plus does not match out of the box. That does not replace backups. It is an insurance-style add-on that can matter when a single drive held the only copy of something irreplaceable.
Buy Red Plus when price-per-TB and matched RAID cost dominate. Buy IronWolf when the Rescue window is worth the usual premium and you want that recovery path documented on the invoice.
Noise, thermals, and review consensus
Winner: slight edge to WD Red Plus in quiet home NAS chatter; treat both as similar 5400-class drives. Published review and owner consensus for this generation of 4TB CMR NAS drives describes both as mid-range acoustic citizens: audible seek chatter in a quiet room, fine inside a closed Synology, QNAP, TrueNAS, or DIY case with decent airflow. Neither is a helium enterprise whisper-quiet unit. Thermals track spindle class and bay packing more than brand paint: leave intake/exhaust clear, avoid stuffing eight warm drives in a sealed desktop case, and expect similar idle/load heat envelopes.
If your NAS sits under a desk in a bedroom, prioritize chassis fans and vibration isolation over obsessing about Red Plus vs IronWolf acoustics. The bigger noise jump is usually the case fan curve, not the 4TB CMR platters themselves.
Who each drive fits
Buy the WD Red Plus 4TB if you want CMR NAS media at the lower typical street price, you are building or expanding a home RAID/SHR volume up to eight bays, and you already keep offsite or cloud backups so recovery insurance is secondary.
Buy the Seagate IronWolf 4TB if you prefer Seagate's NAS tooling and firmware familiarity, you value the Rescue Data Recovery window, or local pricing flips and IronWolf is the cheaper CMR 4TB that day.
Skip both if you need more than ~180TB/year of sustained writes, you want 7200 RPM class performance, or you only need a single USB backup drive. Look at Red Pro / IronWolf Pro, or a simpler portable SSD/HDD for one-off backups, instead of these multi-bay NAS SKUs.
Bottom line
WD Red Plus 4TB and Seagate IronWolf 4TB are peers: CMR, 4TB, SATA, 256MB-class cache, 5400 RPM class, 180TB/year. The Red Plus wins overall for most shoppers because it is usually cheaper for the same core NAS class. IronWolf's clearest differentiator is Rescue Data Recovery on top of the shared three-year warranty. Confirm the exact model numbers (WD40EFPX and ST4000VN006), then View on Amazon for current pricing before you order a full bay set.
