What two 4TB drives provide in RAID1
Two equal 4 TB drives in RAID1 provide roughly 4 TB before formatting and reserved space. Redundancy protects availability in some failures; keep an independent backup.[1]
Western Digital · NAS hard drive buying guide
WD Red Plus 4TB (WD40EFZZ) Buying Guide
Product facts and dated cost
Western Digital WD Red Plus 4TB · Exact identity: WD40EFZZ
4TB decimal capacity · CMR · SATA 6 Gb/s
Catalog amount: $194.99 · historical · Price record: 2026-09-27T13:58:17.239646+00:00. Tax and shipping excluded.
Historical price observation. Recheck the price and availability before buying; this is not a current offer.
WD Red Plus 4TB: specifications and dated store comparison →A 4TB CMR option with 128 MB cache; other 4TB Red Plus suffixes are different SKUs.
One 4 TB WD40EFZZ drive ·3.5-inch SATA ·CMR ·5400 RPM
WD40EFZZ is the 128 MB cache 4TB Red Plus SKU in the September 2025 table: CMR, 5400 RPM, 180 MB/s, 4.5/2.9 W, 24/27 dBA, 550 g. TechRadar's 4TB Red Plus review tested WD40EFPX (256 MB). Firebls tested WD40EFZX. Kakaku lists this MPN with zero owner reviews. YouTube search for WD40EFZZ did not return an exact-MPN benchmark; C7faCi__zLI is WD40EFPX spin-up sound. CDW showed $212.99 on 2026-09-12 with Mfg # WD40EFZZ. This site has not tested the drive. See evidence and test gaps ↓
Is this 4TB drive right for your NAS?
Shared files and backup targets
CMR and the 180 TB/year class suit NAS data storage within the stated limits.[1]
A NAS beside your desk
Enclosure resonance and seek activity need separate assessment.[1]
Latency-sensitive applications
Mechanical storage is capacity-oriented; application response depends on seeks and the whole NAS.[1]
Key hard drive specifications
Full specifications ↗Follow any specification for its full conditions and sources.
Living with it
Capacity, NAS workload and placement
Drive speed is only part of a NAS transfer
The 180 MB/s rating is an internal drive figure. Your NAS processor, network, filesystem, RAID and file sizes determine end-to-end transfers. Small-file applications also encounter mechanical seek delays.[1]
180TB/year workload and the eight-bay design
This model is rated for 180 TB/year of reads and writes. Annual workload is not lifetime writes. Red Plus is designed for up to eight bays; frequent transfers can consume the annual rating even if the drive is not full.[1]
Acoustic ratings and NAS placement
The datasheet lists 24 dBA idle and 27 dBA average seek. These are laboratory ratings, not noise measured at your desk. Mount securely, leave cooling clearance, and avoid relying on brand or family names to predict quietness.[1]
WD40EFPX lab results that must stay on the other column
Mark Pickavance tested WD40EFPX versus ST4000VN006 with AJA, ATTO, CrystalDiskMark, PCMark and Winsat on a PC after a TerraMaster F4-425 Pro 2.5GbE path produced ~296 MB/s, which he flagged as NAS-cache artifact. CrystalDiskMark default read/write were 201.23 / 208.26 MB/s for WD40EFPX. WD40EFZZ has half the cache and its own power/acoustic cells. Do not paste those charts onto this MPN.[5][1]
DXP2800 4TB RAID1 photos are WD40EFPX, not this SKU
Syobon.jp's UGREEN-sponsored DXP2800 article uses two 4TB Red Plus drives. Original photos 07 and 08 show WD40EFPX, MDL WD40EFPX-68C6CN0, not WD40EFZZ. This round does not borrow that article's CrystalDiskMark array numbers (~296 MB/s RAID1 over 2.5GbE) as EFZZ evidence.[8][1]
What still needs a real-world test
We have verified the specifications, but have not found an original test that we can reliably apply to this exact model. The advice above follows the documented features; performance, noise and long-term reliability are not independently established here.
Before you buy
Current and historical WD40EFZZ listings and ownership costs
Dated US listings, not a live lowest-price promise
Newegg $194.99 (2026-09-10, Newegg-sold) and B&H $239.99 (2026-09-08) are unchanged historical rows. CDW showed $212.99 and Add to Cart on 2026-09-12 for Mfg # WD40EFZZ; shipping was not isolated. Target listed the MPN but sold-by Spacebound with no visible USD in the capture. Check the live page before buying.[4][2][6]
Compare the cost of usable storage
Budget for all drives in the array, backup capacity and eventual replacements. Compare the cost after your chosen redundancy overhead.[1]
Include power and the enclosure
The drive is rated at 2.9 W idle and 4.5 W read/write at room temperature. Actual consumption depends on operation; the NAS adds its own power.[1]
Verify the offered unit
Check WD40EFZZ, one 4 TB drive, new condition, the actual seller and regional warranty. A retailer suffix is preserved in offer notes for verification.[1]
Compare stores for this exact model
One 4 TB WD40EFZZ drive ·3.5-inch SATA ·CMR ·5400 RPM Check the total delivered price at the store.
Current price needs checking
Check stores below
5 stores · 0 recent price observations
Newegg
Sold by Newegg
$194.99
Historical price
Stock not confirmed · New
One 4TB 3.5-inch SATA HDD
Observed shipping: $1.99
Observed Oct 9, 2026, 1:24:01 AM UTC[11]
View exact product at NeweggBest Buy
Seller not recorded
$194.99
Historical price
Currency not confirmed
Stock not confirmed · Condition not recorded
Observed Sep 27, 2026, 1:58:17 PM UTC[12]
View exact product at Best BuyCDW
Sold by CDW
$212.99
Historical price
Stock not confirmed · New
One 4 TB drive
Not isolated from the captured HTML. US CDW catalog; tax and shipping not confirmed in this capture.
Observed Sep 12, 2026[6]
View exact product at CDWB&H
Seller not recorded
$239.99
Historical price
Currency not confirmed
Stock not confirmed · Condition not recorded
Observed Sep 27, 2026, 3:10:27 PM UTC[9]
View exact product at B&HWestern Digital
Seller not recorded
$239.99
Historical price
Currency not confirmed
Stock not confirmed · Condition not recorded
Observed Sep 26, 2026, 4:06:49 PM UTC[10]
View exact product at Western DigitalPrices are dated observations. Confirm the model, seller, condition, stock and delivered total at the store. Older prices remain visible as history. Links may earn a commission.
Compatibility, capacity and backup questions
Is this model CMR?
Yes; the official exact WD40EFZZ column specifies CMR.[1]
Does the MTBF rating predict years of life?
No. It is a population estimate under specified workload and temperature conditions, not a promise for one drive.[1]
Does the NAS bay rating mean universal compatibility?
No. Check the exact enclosure, firmware and capacity qualification.[1]
Does RAID replace a backup?
No. Redundancy does not protect against every deletion, malware incident or whole-device loss. Keep an independent copy.[1]
Sources
Research updated Sep 12, 2026. Individual source check dates are listed below. Measurements belong to the named reviewers; tested configurations and software versions may differ from the product you buy.
- [1] WD Red Plus HDD data sheet (September 2025) ↗
Checked Sep 11, 2026 · September 2025 p.2 column WD40EFZZ; footnotes 1–10
- [2] B&H WD40EFZZ product listing ↗
Checked Sep 8, 2026 · MFR WD40EFZZ-SPCPAN0; exact base MPN, 4 TB and quantity 1; In Stock and Add to Cart.
- [3] Western Digital WD40EFZZ product listing ↗
Checked Sep 8, 2026 · Exact SKU title/model confirmed; price and inventory appear as unresolved template fields. No stock inference from hidden buttons.
- [4] Newegg: WD40EFZZ current US new listing ↗
Checked Sep 10, 2026 · Exact MPN in H1; selected main offer shows Add to cart, seller Newegg, and a visible price of $194.99.
- [6] CDW WD Red Plus 4 TB WD40EFZZ ↗
Checked Sep 12, 2026 · Mfg # WD40EFZZ; $212.99; Add To Cart; 128 MB buffer; 5400 rpm; 4 TB; 3.5-inch SATA 6 Gb/s
- [9] B&H product price observation ↗
Checked Sep 27, 2026 · Captured observation; sha256:df0bf4dd187165ee71a7bee77b1553eaf130efdcd28f3a067df22bf955f34a91
- [10] Western Digital product price observation ↗
Checked Sep 26, 2026 · Captured observation; sha256:aa5360a321767038266d5de5e564777d97bb0e9ef623f521fc836f85f3afc77c
- [11] Newegg product price observation ↗
Checked Oct 9, 2026 · newegg-main-item; sha256:0c0fad51557fe2df6e56d778b067f4978483b5cd2f988d609d4d2a872e143f7a
- [12] Best Buy product price observation ↗
Checked Sep 27, 2026 · Captured observation; sha256:2bf6c310d3a5c0e4766d02d95744e2060dc7461b182fa7c7f53aeab26d9a713b
Research and review record
- Research: Grok 4.6 · Targeted additional original-source research for five mainstream HDDs.
- Self-check: Grok 4.6 · Source identity, method and data self-check; WD original session also verified the parent-supplied Zigsow lead.
- Independent review: GPT-6 (Codex) · Original evidence verification, applicability decisions and correction of incomplete case follow-up and document interpretation.
- Editorial integration: GPT-6 (Codex) · Preserve source history, update five local research records and existing coverage report.
Independent review completed for the scope recorded in the audit.
Source evidence and review history (JSON)