This article covers WD20EFZX [WD Red Plus（2TB 3.5インチ SATA 6G 5400rpm 128MB CMR）].

Overview

Western Digital's WD Red Plus series is purpose-built for NAS (Network Attached Storage) environments, and the WD20EFZX is a 2TB model that exemplifies this focus. This 3.5-inch internal hard drive features a SATA 6Gb/s interface, a 5400RPM spindle speed, and 128MB of cache memory, delivering sequential read/write speeds of up to 175MB/s. What truly sets it apart is its use of CMR (Conventional Magnetic Recording) technology, which provides consistent write performance even under sustained loads. Designed for home NAS units, small office file servers, and RAID arrays, the WD20EFZX prioritizes reliability over raw speed. Unlike SMR (Shingled Magnetic Recording) drives, CMR drives do not suffer from performance degradation after large write operations, making them far more suitable for multi-drive configurations where rebuild times and data integrity are critical. This drive is built for 24/7 operation, with a workload rate limit that ensures longevity in always-on environments. In the broader market, the WD Red Plus sits as an entry-to-mid-range NAS HDD. It offers a compelling balance of cost, capacity, and reliability for users who need dependable storage without stepping up to enterprise-grade drives like the WD Red Pro (7200RPM) or Ultrastar series. Compared to consumer-grade drives like the WD Blue, the Red Plus includes features such as TLER (Time-Limited Error Recovery), which prevents drives from being dropped from RAID arrays during error recovery.

Compatibility Guide

The WD20EFZX is a standard 3.5-inch SATA internal hard drive, compatible with virtually any device that has a SATA port. Here are the key compatibility details: Form Factor: 3.5-inch (101.6mm x 147mm x 26.1mm) — requires a 3.5-inch drive bay Interface: SATA 6Gb/s (backward compatible with SATA 3Gb/s and 1.5Gb/s) Compatible Devices: Desktop PCs, NAS units (QNAP, Synology, ASUSTOR, etc.), RAID controllers, external drive enclosures Power: Standard SATA power connector (requires both 5V and 12V rails) * Note: Not compatible with 2.5-inch bays, slim desktops, or laptops without an adapter

Product Info

The WD20EFZX was released around 2020 and remains a current product as of mid-2026. It carries a standard 3-year manufacturer warranty (may vary by region). Pricing on Japan is approximately ¥28,500, which is typical for a 2TB NAS-grade CMR HDD in this class. Market positioning: Entry-to-mid-range NAS HDD. The CMR recording technology makes it a step above SMR-based budget NAS drives (WD Red non-Plus), offering superior reliability for RAID configurations. However, its 5400RPM spindle speed means it trails the WD Red Pro (7200RPM) in random I/O performance.

Best Use Cases

Home NAS User: Ideal for users running a QNAP or Synology NAS for photo backups, media streaming, and document storage. The CMR technology ensures stable performance in RAID 5 or RAID 6 arrays, even during rebuilds. Not suitable for 4K video editing workloads that demand high sequential throughput. Small Office File Server: Perfect for teams of 2-10 people sharing documents and project files. Low power consumption and heat output make it a good fit for compact, passively-cooled NAS enclosures. For environments with heavy concurrent access (10+ users), consider the WD Red Pro or an enterprise drive. * Data-Conscious DIY Builder: Great as a secondary data drive in a desktop PC, complementing a fast NVMe SSD for the OS and applications. The CMR design ensures consistent write speeds for large backups. Not recommended as a primary game drive — load times will be noticeably longer than even a SATA SSD.

Things to Consider

The WD20EFZX's 5400RPM spindle limits sequential throughput to around 175MB/s. If you frequently transfer large files (e.g., 4K video projects, database backups), a 7200RPM drive like the WD Red Pro or Seagate IronWolf Pro will offer 30-40% faster transfer rates. Additionally, the 2TB capacity is modest by modern standards; users with growing media libraries may find themselves upgrading sooner than expected. A key caution: visually, the WD Red Plus (CMR) and the standard WD Red (SMR) look nearly identical. Always verify the model number — "EFZX" indicates CMR (Red Plus), while "EFAX" indicates SMR (non-Plus). Using SMR drives in a RAID array can lead to timeouts during rebuilds, especially with larger capacities. Competitors include the Seagate IronWolf (CMR, similar price) and Toshiba N300 series. The IronWolf offers comparable performance, while the WD Red Plus is often praised for quieter operation. If you need more than 2TB, consider the WD40EFZX (4TB) or WD60EFZX (6TB) within the same Red Plus family. ## FAQ
Q: Can the WD20EFZX be used in a RAID configuration? A: Yes, absolutely. The WD Red Plus series is designed and tested for RAID 0, 1, 5, 6, and 10 environments. The CMR recording technology ensures stable write performance during array rebuilds

Product Disclosure (Amazon)

  • Manufacturer: ウエスタンデジタル(Western Digital)
  • Seller: デザイナーズ アクア
  • Fulfilled by: Amazon
  • ASIN: B08VH891FS
  • Note: This article covers a manufacturer-made product based on Amazon listing details.