Western Digital WD Blue 4TB Hard Drive (WD40EZAX): specs and who it suits

The Western Digital WD Blue 4TB (WD40EZAX) is a 3.5-inch internal hard drive for desktop computers. Western Digital positions the WD Blue range for everyday computing, office and web use, and as a primary or secondary drive in desktop PCs. It is useful when you need a lot of space for documents, photos, video and backups.

What the specs mean

4TB capacity. That is a lot of room for files. Western Digital notes that it counts 1TB as one trillion bytes, so the capacity your operating system displays will be somewhat lower, which is normal for all drives.

5400 RPM. The platters spin at 5400 revolutions per minute. Slower spin speeds typically mean less noise and heat than 7200 RPM drives, while sequential speeds are usually a little lower. For bulk storage, that is a reasonable balance.

256 MB cache. The cache is a small buffer that holds recently used data, which helps smooth short bursts of reads and writes.

SATA 6 Gb/s. This is the standard connection for internal drives. SATA is backwards compatible, so the drive generally works on older SATA ports, but at the speed those ports support. In practice, the platters limit the speed rather than the interface.

3.5-inch size. The drive is 5.8 x 4.0 x 1.0 inches and weighs 1.3 lb. It needs a 3.5-inch bay, which most desktop towers have. It will not fit a typical laptop without an external enclosure, since laptops use smaller drives.

Hard drive or SSD?

A hard drive stores data on spinning platters, while an SSD uses flash memory. SSDs are much faster at starting up, loading programs and opening many small files. Hard drives typically offer far more capacity per unit. Many desktop builders therefore use an SSD for the operating system and programs, and a hard drive like this one for large libraries, media and backups.

Software and warranty

Western Digital says the drive includes access to Acronis True Image WD Edition cloning software, which can copy an existing drive onto a new one when you upgrade. The listing states a 2-year limited warranty. The product line is available in capacities up to 8TB, according to the brand.

Who it suits

It suits desktop owners who need extra storage, people building a media or photo library, and anyone setting up a backup drive. It is less suited to uses that need fast random access, such as the drive an operating system boots from.

What to check before you buy

• Bay and ports: confirm a free 3.5-inch bay, a SATA data port and a SATA power connector.
• Cables: the listing doesn't mention a data cable, so check whether you have one.
• Backups: one drive is not a backup. Keep important files in more than one place.
• Noise and vibration: hard drives make some sound, so consider where the PC sits.
• Use case: check that a hard drive's speed fits your workload.

The short version

• Western Digital WD Blue 4TB internal hard drive, model WD40EZAX.
• 3.5-inch, 5400 RPM, 256 MB cache, SATA 6 Gb/s.
• Includes Acronis True Image WD Edition cloning software; 2-year limited warranty.
• Suited to bulk storage in desktops, usually alongside an SSD.

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