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WD Red Plus vs Seagate IronWolf

WD Red Plus and Seagate IronWolf are the two most popular NAS hard drive lines for home and small-business use. Both are designed for always-on, multi-bay enclosures and both offer CMR models across most capacities. The right choice often comes down to price at your target capacity, local availability, and which ecosystem your NAS vendor recommends.

Quick comparison

WD Red Plus is rated for 1–8 bay NAS systems with a 180 TB/year workload rating. IronWolf covers 1–8 bays with a 180 TB/year rating and adds built-in rotational vibration (RV) sensors and IronWolf Health Management (IHM) for compatible Synology, QNAP, and Asustor systems. Both use CMR at most capacities. For most buyers, the best deal per TB wins.

Quick Verdict

Who this is for
NAS builders choosing between the two mainstream NAS drive lines for home or small-office Synology, QNAP, TrueNAS, or Unraid systems.
What usually wins
The cheaper CMR option at your target capacity. Both lines perform similarly — pick whichever is priced lower per TB when you buy. IronWolf edges ahead if your NAS supports IronWolf Health Management.
Prioritise
CMR recording at your target capacity. Then lowest price per TB. Ecosystem features (IHM vs NASware) are a tiebreaker, not a primary factor.

Prices updated hourly from Amazon US and UK. All links go directly to the retailer.

WD Red Plus — Current Prices

Western Digital Red Plus NAS drives sorted by price per terabyte. All CMR, rated for 1–8 bay NAS enclosures with a 180 TB/year workload.

All WD Red Models

All WD Red drives including Red, Red Plus, and Red Pro. Red Pro adds a 300 TB/year workload rating and is designed for up to 24-bay rackmount NAS systems.

Seagate IronWolf — Current Prices

Seagate IronWolf NAS drives sorted by price per terabyte. Includes AgileArray dual-plane balance, RV sensors, and IronWolf Health Management on supported NAS hardware.

£12.19/TB New

Seagate IronWolf ST4000VN008 4TB Internal Hard Drive, NAS HDD, 3.5 Inch, 5900 rpm, CMR, 64 MB Cache, SATA 6 GB/s, Silver, 3 Years Data Rescue Service

16 TB Internal 3.5" SATA
£195.00 Amazon UK
$24.64/TB New

Seagate IronWolf Pro 28TB Enterprise NAS Internal HDD Hard Drive – CMR 3.5 Inch SATA 6Gb/s 7200 RPM 512MB Cache for RAID Network Attached Storage, Rescue Services (ST28000NT000)

28 TB Internal 3.5" SATA
$689.99 Amazon US
$25.00/TB New

Seagate IronWolf 14TB NAS Internal Hard Drive HDD – 3.5 Inch SATA 6Gb/s 7200 RPM 256MB Cache for RAID Network Attached Storage (ST14000VN0008)

14 TB Internal 3.5" SATA
$349.99 Amazon US
$25.00/TB New

Seagate IronWolf Pro, 20 TB, Enterprise NAS Internal HDD –CMR 3.5 Inch, SATA 6 Gb/s, 7,200 RPM, 256 MB Cache for RAID Network Attached Storage (ST20000NT001)

20 TB Internal 3.5" SATA
$499.99 Amazon US
£26.00/TB New

Seagate IronWolf Pro 20TB, Enterprise Internal NAS HDD, CMR 3.5 Inch, SATA 6GB/s, 7.200 RPM, 256MB Cache for RAID NAS, Rescue Services - Frustration Free Packaging (ST20000NTZ01)

20 TB Internal 3.5" SATA
£519.99 Amazon UK
£26.43/TB New

Seagate IronWolf Pro 28TB, NAS internal hard drive, 3.5", 7200 U/Min, CMR, 512 MB Cache, SATA 6 GB/S, Data Rescue Service (ST28000NTZ00)

28 TB Internal 3.5" SATA
£739.99 Amazon UK
$28.13/TB New

Seagate IronWolf Pro 16TB 7200 RPM SATA 6Gb/s 3.5" NAS HDD (ST16000NE000)

16 TB Internal 3.5" SATA
$450.00 Amazon US
$29.36/TB New

Seagate IronWolf 14TB NAS Internal Hard Drive HDD – CMR 3.5 Inch SATA 256MB Cache for RAID Network Attached Storage – Frustration Free Packaging (ST14000VN0008)

14 TB Internal 3.5" SATA
$410.99 Amazon US

CMR NAS Drives — Both Brands

Conventional Magnetic Recording drives from both WD and Seagate, filtered to CMR only. Essential for RAID and ZFS arrays where SMR write performance is a concern.

Why this matters: CMR (Conventional Magnetic Recording) handles random writes and RAID rebuilds significantly better than SMR. If you are running any form of RAID, ZFS, or Btrfs, CMR is strongly recommended. Both WD Red Plus and IronWolf offer CMR at most capacity points.

£12.19/TB New

Seagate IronWolf ST4000VN008 4TB Internal Hard Drive, NAS HDD, 3.5 Inch, 5900 rpm, CMR, 64 MB Cache, SATA 6 GB/s, Silver, 3 Years Data Rescue Service

16 TB Internal 3.5" SATA
£195.00 Amazon UK
$24.64/TB New

Seagate IronWolf Pro 28TB Enterprise NAS Internal HDD Hard Drive – CMR 3.5 Inch SATA 6Gb/s 7200 RPM 512MB Cache for RAID Network Attached Storage, Rescue Services (ST28000NT000)

28 TB Internal 3.5" SATA
$689.99 Amazon US
$25.00/TB New

Seagate IronWolf 14TB NAS Internal Hard Drive HDD – 3.5 Inch SATA 6Gb/s 7200 RPM 256MB Cache for RAID Network Attached Storage (ST14000VN0008)

14 TB Internal 3.5" SATA
$349.99 Amazon US
$25.00/TB New

Seagate IronWolf Pro, 20 TB, Enterprise NAS Internal HDD –CMR 3.5 Inch, SATA 6 Gb/s, 7,200 RPM, 256 MB Cache for RAID Network Attached Storage (ST20000NT001)

20 TB Internal 3.5" SATA
$499.99 Amazon US
£26.00/TB New

Seagate IronWolf Pro 20TB, Enterprise Internal NAS HDD, CMR 3.5 Inch, SATA 6GB/s, 7.200 RPM, 256MB Cache for RAID NAS, Rescue Services - Frustration Free Packaging (ST20000NTZ01)

20 TB Internal 3.5" SATA
£519.99 Amazon UK
£26.43/TB New

Seagate IronWolf Pro 28TB, NAS internal hard drive, 3.5", 7200 U/Min, CMR, 512 MB Cache, SATA 6 GB/S, Data Rescue Service (ST28000NTZ00)

28 TB Internal 3.5" SATA
£739.99 Amazon UK
$27.72/TB New

WESTERN DI - WD Red PRO Nas Hard Drive WD181KFGX - HD - 6176921

18 TB Internal 3.5" SATA
$499.00 Amazon US
$28.13/TB New

Seagate IronWolf Pro 16TB 7200 RPM SATA 6Gb/s 3.5" NAS HDD (ST16000NE000)

16 TB Internal 3.5" SATA
$450.00 Amazon US

How to Choose

WD Red Plus and Seagate IronWolf are more alike than different. Here is what actually separates them.

CMR availability

Both lines offer CMR at most capacity points, but verify before buying — entry-level models have occasionally used SMR. CMR is essential for RAID and ZFS arrays where SMR write behaviour causes rebuild issues.

Bay count and workload

Both are rated for 1–8 bays and 180 TB/year workloads. If you need more, step up to Red Pro or IronWolf Pro (both rated for up to 24 bays and 300 TB/year). For a typical home NAS, standard models are sufficient.

Ecosystem features

IronWolf includes rotational vibration sensors and IronWolf Health Management (IHM) on compatible NAS hardware. WD Red Plus uses NASware 3.0 firmware for multi-bay optimisation. IHM provides proactive drive health alerts if your NAS supports it — a useful feature for unattended systems.

Price at capacity

Pricing between Red Plus and IronWolf shifts frequently. At any given capacity point, one brand is often noticeably cheaper than the other. Check both columns and buy the better deal — the performance and reliability difference is negligible for home NAS workloads.