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 white thermal paste which help to transfer heat from the controllers to the hard disk drive chassis.

The WD4000FYYZ drive uses the Marvell 88i9346-TFJ2 drive controller, which is incidentally the same controller used in the 1 TB Western Digital VelociRaptor (WD1000DHTZ). This is a dual-core processor, which would boost its ability to handle multiple transactions simultaneously. It also uses an ST Microelectronics motor drive controller, 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.

It appears that Western Digital does not use a particular brand of SDRAM chip to provide the drive's 64 MB cache. In some cases, the SDRAM chip used was the Hynix H5PS5162GFR-S6C. In our unit, Western Digital used the Winbond W9751G6JB-25 which is a 64 MB DDR2 SDRAM chip, with 4 memory banks and an operating speed of 800 MHz DDR with 5-5-5 timings. It therefore has a maximum transfer rate of 800 MB/s, which is fast enough to keep up with the SATA 6 Gb/s interface.

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 RE hard disk drive boasts a maximum sustained internal (platter-to-buffer) transfer rate of 171 MB/s and a large 64 MB buffer.

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.

From what we can tell, Western Digital ships some drives with a jumper and others without a jumper. Since our OEM unit did not come with one, it is likely that only retail drives come with the jumper.

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 3 Gb/s speed negotiation.

Breather Holes

The Western Digital RE (WD4000FYYZ) hard disk drive does not have any clearly-marked breather holes on the top plate.

The underside has two breather holes (see picture on the right) near the top of the drive. These holes 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 the holes!

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