Western Digital 4TB WD Red NAS Internal Hard Drive HDD - 5400 RPM, SATA 6 Gb/s, SMR, 256MB Cache, 3.5" - WD40EFAX
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AI Verdict
This 4TB, 5400 RPM, SATA 6 Gb/s SMR drive is for basic, low-write-activity storage, not for active NAS environments.
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Pros
- Offers 4 TB of storage capacity in a 3.5-inch form factor.
- Features NASware firmware for compatibility with NAS systems.
- Supports a workload rate of up to 180 TB/yr, suitable for personal and home office use.
- Includes a 256MB cache for buffering data.
- Comes with a 3-year limited warranty.
Cons
- Uses SMR (Shingled Magnetic Recording) technology, which significantly degrades write performance, especially during sustained writes or RAID rebuilds.
- Users report the drive making NAS systems very slow and unresponsive during heavy write operations.
- The '5400 RPM class' designation is vague, not a specific 5400 RPM speed.
- Not suitable for multi-drive NAS arrays that require frequent data writes or rebuilds due to SMR limitations.
- Many users advise against this specific model (WD40EFAX) for NAS use, recommending CMR alternatives like WD Red Plus instead.
Dimension Scores
The 5400 RPM class and SMR technology lead to significantly degraded sustained write speeds, particularly in NAS environments.
While WD Red drives typically have a reputation for reliability, the SMR technology introduces performance reliability concerns in NAS, not necessarily mechanical failure.
4 TB is a common and useful capacity for home NAS or personal storage, offering a balance between cost and storage space.
Physically compatible with NAS systems, but the SMR technology creates functional incompatibility for many common NAS use cases, leading to poor performance.
Best For
- Single-drive backup solutions where data is written infrequently.
- Archival storage for media libraries that are mostly read-only.
- Personal cloud storage with minimal concurrent write access.
- Home office NAS systems with light, intermittent data writes and ample idle time.
Not Recommended For
- Multi-bay NAS systems requiring RAID configurations with frequent writes or rebuilds.
- Environments demanding consistent, high-speed write performance.
- Critical data storage where drive failure or slow rebuilds are unacceptable.
- Users expecting performance comparable to CMR drives.
Watch Out For
- The SMR technology means that during heavy write operations, like initial data loading or RAID rebuilds, performance can drop dramatically, making your NAS unresponsive.
- If you're replacing a failed drive in a RAID array, the rebuild process with this SMR drive can take an extremely long time and potentially stress other drives in the array.
- Western Digital's '5400 RPM class' is not a fixed 5400 RPM, which can lead to inconsistent performance expectations.
- Many users mistakenly purchase this 'Red' drive for NAS, unaware of the SMR limitation, leading to frustration and the need to replace drives.
Full Specifications
| ASIN | B083XVY99B |
| Brand | Western Digital |
| Color | Red |
| Series | WD Red |
| Language | English, English, English, English, English |
| Hard Drive | 4 TB Mechanical Hard Disk |
| Item Weight | 1.23 pounds |
| Manufacturer | Western Digital |
| Special Feature | Portable |
| Flash Memory Size | 4 TB |
| Hardware Platform | Mac, PC |
| Installation Type | Internal Hard Drive |
| Item model number | WD40EFAX |
| Compatible Devices | Storage System |
| Product Dimensions | 1.03 x 5.79 x 4 inches |
| Hard Disk Interface | Serial ATA-600 |
| Hard Drive Interface | Serial ATA-600 |
| Hard Disk Description | Mechanical Hard Disk |
| Hard Disk Form Factor | 3.5 Inches |
| Item Dimensions LxWxH | 1.03 x 5.79 x 4 inches |
| Connectivity Technology | SATA |
| Digital Storage Capacity | 4 TB |
| Hard Drive Rotational Speed | 5400 RPM |
| Standing screen display size | 24 Inches |
| Is Discontinued By Manufacturer | No |
What Buyers Say
The biggest takeaway from user feedback is the widespread frustration with the SMR technology in this specific WD Red drive (WD40EFAX) when used in NAS systems. Many buyers, expecting a 'NAS drive,' found their systems becoming incredibly slow and unresponsive during tasks like RAID rebuilds or large data transfers. The general consensus on Reddit is to avoid this model for any serious NAS application and opt for CMR drives like the WD Red Plus instead. While it offers 4TB of storage, its performance profile makes it a poor choice for the very purpose it's marketed for.
“Man, I bought this 'Red' drive for my Synology and it's been a nightmare. Rebuilding my array took forever, and now just copying files makes the whole thing crawl. Should've just spent the extra for a Red Plus, this SMR garbage is not for NAS, seriously.”
Common Praise
- Provides 4TB of storage capacity.
- Works as a basic, low-activity storage drive.
- Relatively quiet during idle operation (not explicitly stated in search results, but common for 5400 RPM drives).
Common Complaints
- Extremely slow write speeds during sustained operations due to SMR.
- Causes NAS systems to become unresponsive during RAID rebuilds or large data transfers.
- Confusion between this SMR 'Red' drive and the CMR 'Red Plus' series.
- Many users feel misled by the 'NAS' branding given the SMR limitations.
Ownership Tips
- Initial setup and data transfer to the drive can be agonizingly slow if you're moving a lot of data at once.
- If used in a RAID array, a single drive failure and subsequent rebuild will likely bring your entire NAS to its knees for days.
- The drive performs adequately for light, infrequent writes, but any heavy activity exposes its SMR limitations.
- Monitoring your NAS's performance metrics will clearly show the bottlenecks caused by this SMR drive during write-intensive tasks.
Frequently Asked Questions
Is this drive suitable for a multi-bay NAS system?
No, this drive uses SMR technology, which can cause significant performance issues, especially during RAID rebuilds or sustained writes in multi-bay NAS systems. It's generally advised to use CMR drives for such setups.
What is the actual RPM of this drive?
Western Digital specifies this as a '5400 RPM class' drive. This means it operates around 5400 RPM, but the exact speed can vary and isn't a fixed 5400 RPM.
What's the difference between this WD Red drive and a WD Red Plus drive?
The primary difference is the recording technology. This WD Red (WD40EFAX) uses SMR, while WD Red Plus drives use CMR (Conventional Magnetic Recording). CMR drives offer consistent write performance, making them much better for NAS applications.
Can I use this drive for a desktop computer?
Yes, you can use this drive in a desktop computer for general storage or backup. The SMR limitations are less noticeable in single-drive, intermittent-write scenarios compared to a NAS environment.
Will this drive work with my Synology NAS?
While it may be physically compatible, many users report severe performance degradation and unresponsiveness when using SMR WD Red drives like this one in Synology NAS devices, especially during array operations.
Buying Guide
When you're looking at hard drives, especially for something like a NAS, don't just look at capacity and brand. You need to understand the underlying technology, because it directly impacts how the drive performs. For NAS, you're often dealing with multiple drives working together, and if one can't keep up, the whole system suffers. This drive uses SMR, which is a big deal for NAS.
SMR (Shingled Magnetic Recording)
Think of SMR like overlapping shingles on a roof. To write new data, the drive might have to rewrite adjacent 'shingles,' which takes more time. This is fine for archiving (write once, read many), but terrible for constant writes or RAID rebuilds in a NAS, where performance will tank.
5400 RPM Class
This is the rotational speed of the platters inside the drive. Higher RPM (like 7200 RPM) generally means faster data access. '5400 RPM class' is a bit vague, but it tells you this isn't a speed demon, and combined with SMR, it's definitely not for performance-critical tasks.
NASware Firmware
This is special software on the drive designed to improve compatibility and performance in NAS environments, handling things like error recovery and power management. However, even with NASware, SMR technology can still be a major bottleneck for NAS use.
Alternatives
If this drive doesn't fit your needs, search for 4TB or larger internal hard drives explicitly stating CMR (Conventional Magnetic Recording) technology, or look for 'Plus' or 'Pro' versions of NAS-specific drive lines.
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