Looking at the drive itself, you may be forgiven for thinking that this drive is just like any other Wester Digital hard drive currently on the market. This is where you're wrong. The Caviar RE2 has a few performance and specification changes from its other models, like the Caviar SE16.
Western Digital has two versions of the new Caviar RE2 series of hard drives. We'll cover the WD4000YR model first. Unlike the SE16 series, the RE2 WD4000YR model only uses a 150MB/s transfer protocol, which is half the 300MB/s that SATA-II offers. Since the drive is set for RAID setups, you aren't demanding as much on a single channel, this is the reasoning behind Western Digital's use of only 150MB/s transfer rate on this particular mode.
The second and more expensive model in the Caviar RE2, which we have on the test bed today, is the WD5000YS. This model is the same as the WD4000YR except it includes 300MB/s transfer speeds making it fully SATA-II compliant.
Since the RE2 WD4000YR model lacks the 300MB/s transfer speed, it can't be classed as SATA 2.5 compliant. However, you will find all the other SATA 2.5 specs on this drive, namely staggered spin-up and Native Command Queuing (NCQ). The drive has a seek time of 8.7ms and that makes it 0.2ms quicker than the SE16. This is due to the denser platters used in the RE2 series of drives. Denser platters means the heads cover more territory in a shorter amount of rotation time.
Western Digital's circuitry is extremely clean. There are no chips on the lower PCB. These have all been sandwiched between the PCB and the drives lower casing. On the back of the drive, we have a single SATA data port that supports the new snap lock SATA data cables, so no more cable pops. The drive supports both SATA and Molex power connectors, but you are warned on the top of the drive to use one of the other, not both.
The RE2 come in sizes from 100GB up to 500GB with 16MB of cache. These seek times are better then Seagate's 7200.9 series hard drives, which we are comparing against today, with seek times of 9.5ms.