The 4 TB Western Digital Red Pro (WD4001FFSX)

Although Western Digital positioned the 4 TB Western Digital Red Pro hard disk drive as the enhanced version of the 4 TB Western Digital Red (WD40EFRX), it's really the NAS-optimized version of the 4 TB Western Digital Black Gen. 2 (WD4003FZEX). Just take a look at this comparison of the three drives :

Like many other 3.5" desktop hard drives, the 4 TB Western Digital Red Pro drive has a label on the top plate and an uncovered PCB on the underside. The label has a lot of important information, like the hard drive model, storage capacity as well as its date and place of manufacture. This particular drive was manufactured in Thailand on the 1st of June, 2014. Interestingly, Western Digital also added a QR code so you can scan it using your smartphone to learn more about the WD Red Pro hard disk drive.

While this is an Advanced Format drive, there is no warning on the label about using WD Align with older operating systems like Windows XP. This is because Western Digital does not expect this drive to be used with older operating systems like Windows XP. You can use this drive in Windows XP or even Windows 98, but you will be limited to the first 2.1 TB.

Connectors & Jumpers

This is a Serial ATA hard drive, with native support for SATA 6 Gb/s. However, it is backward-compatible so you will have no problem using it with older SATA 3 Gb/s controllers.

The SATA 6 Gb/s interface is necessary for optimal performance since this WD Red Pro hard disk drive boasts a maximum sustained internal (platter-to-buffer) transfer rate of 171 MB/s and a large and fast DDR2 SDRAM cache.

Like all Serial ATA drives, it comes the standard SATA data (left) and power (right) connectors and is hot-pluggable. That means you can connect and disconnect this hard disk drive to your PC while it's still running.

To the left of the SATA connectors is the jumper block. However, Western Digital does not provide any jumper with their drives. This is because the jumper block should only be used in exceptional cases.

According to Western Digital, jumpering pins 1 and 2 enables Spread Spectrum Clocking (SSC). Placing the jumper across pins 5 and 6 will force the drive to use the slower SATA 3Gbits/s transfer speed. This is only necessary for certain SATA controllers that do not properly implement the SATA 6 Gb/s speed negotiation.

Breather Holes

The 4 TB Western Digital Red Pro hard disk drive does not have any clearly-marked breather holes on the top plate. The underside has a breather hole (see picture on the right) near the top of the drive. This hole must not be covered.

Breather holes allow condensation inside the hard drive to escape. They also equalize the hard drive's internal pressure with the ambient air pressure. The hard disk drive needs them to function properly, so please make sure you do not occlude these holes!

Peeking Under The PCB

Western Digital has a penchant for keeping all surface-mounted components on the reverse side of the PCB - to prevent static damage and to allow for better cooling. With the PCB out of the way, you can see the two white thermal pads which help to transfer heat from the controllers to the hard disk drive chassis.

The 4 TB Western Digital Red Pro shares a lot of similarity with the 4 TB Western Digital Black Gen. 2 (WD4003FZEX) and the 4 TB Western Digital Re (WD4000FYYZ) enterprise-grade hard disk drive, sharing similar specifications and using the same components too. They all use the Marvell 88i9346-TFJ2 drive controller, which is also used in the 3 TB Western Digital Red (WD30EFRX) and the 1 TB Western Digital VelociRaptor (WD1000DHTZ). This is a dual-core processor, which would boost its ability to handle multiple transactions simultaneously.

The 4 TB Red Pro drive also uses a customised ST Microelectronics motor drive controller (WDHC8TD), which features the proprietary Smooth Drive pseudo-sinusoidal digital drive technology. Smooth Drive allows the hard disk drive to minimize torque ripple to reach a higher track density as well as reduce noise levels.

The 4 TB Western Digital Red Pro also uses the Samsung K4T51163QJ-BCE7, the same memory chip used in the 4 TB Western Digital Black Gen. 2 and the 4 TB Western Digital Re. This is a 64 MB DDR2 SDRAM chip, with 4 memory banks and an operating speed of 800 MHz DDR. While this is the same operating speed as the DDR2-800 memory chip used in the 4 TB Western Digital Red (WD40EFRX) hard disk drive, the Samsung K4T51163QJ-BCE7 has faster 5-5-5 timings (instead of 6-6-6).

Like the 4 TB Western Digital Black Gen. 2 drive, the 4 TB Red Pro ships with double the flash memory capacity of the 4 TB Western Digital Red drive. Western Digital used a Winbond 25Q80BLVIG in the 4 TB Red Pro, which has a storage capacity of 8 Mbits (1024 KB) and a continuous transfer rate of 200 Mbits/s (25 MB/s).

Finally, the 4 TB Red Pro hard disk drive features two shock sensors, just like the 4 TB Western Digital Black Gen. 2 and the 4 TB Western Digital Re. The two sensors allow the drive to better detect subtle shock events and dynamically adjust the flying height of the read/write heads to avoid head crashes.

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