Western Digital Caviar Black: WD1002FAEX-00Z3A0, 1 TB
Western Digital keeps on giving us something new on a regular basis. The more new products the company offers, the more market segments it covers and the more frequently its name is repeated in the news.
The latest piece of news from Western Digital is the update of the Caviar Black series. It now includes a 1-terabyte model with a 64MB buffer and a SATA 600 interface. Yes, this is WD’s answer to Seagate’s Barracuda XT. We have already seen the 64MB cache buffer in the 2TB model but the new interface is indeed a unique feature of this HDD (there is also the recently updated VelociRaptor series but we will talk about it in more detail in an upcoming review). The new HDD has only two platters and, apparently, a combined heads actuator like in the 2TB model (it means that besides the main electro-mechanical actuator, there is a secondary piezoelectric actuator to fine-tune the head’s position in a narrow (a few tracks wide) zone).
Western Digital Caviar Black: WD1001FALS-00J7B0, -00E8B0 and -00E3A0, 1 TB
We’ve got three older drives from Western Digital to compare the new one with. They come from different subseries (J7, E8 and E3). Our practice suggests that WD’s subseries can differ a lot, so we will see what difference we have with the 7200RPM products. By the way, we were trying the different subseries to find a model with two rather than three platters – we had a suspicion that such models had come to retail already.
Western Digital Caviar Green: WD20EARS-00S8B1, 2 TB
And finally, here is a 2TB model from WD’s power-efficient series. It belongs to the new generation of HDDs with 64MB cache and 4KB sectors (Western Digital calls this “Advanced Format”). As this technology provokes a number of questions and hot arguments, we’d like to briefly repeat the facts we said in our first overview of it.
The Advanced Format is a variant of the Long Data Sector technology that describes the transition of HDDs from 512-byte to 4-kilobyte sectors. Storing 4 KB of data will now require one new sector instead of eight older sectors. As a result, the same amount of data takes less space on the platters while the ECC field gets larger, which means that the HDD can store more data and is more reliable. Western Digital’s Advanced Format implementation supports full emulation of 512-byte sectors: for any electronic devices communicating with the HDD, the latter is represented as having 512-byte sectors, but its platters are actually formatted in 4KB sectors each of which contains eight virtual 512-byte sectors. All the required address translations are performed by the HDD’s electronics and are no concern of the user.
The biggest downside of this emulation is its interaction with Windows XP which, when formatting a hard disk, reserves the first 63 sectors (512 bytes each) and begins the partition at sector 64. As a result, all requests in 4KB data blocks prove to be shifted by 512 bytes relative to the hard disk’s sectors (the real sectors, not the emulated ones), provoking a performance hit at writing. Instead of just writing a single block of data, the HDD has to read two blocks, modify them, and only then write them to the platter.
This problem can be solved in two ways. You can close the HDD’s pins 7 and 8 with a jumper to automatically shift the whole logical structure by 512 bytes. Or you can use the WD Align utility which can be downloaded from the Western Digital website. This tool shifts the already existing partitions on the HDD, aligning its logical structure to the physical sectors.
This alignment provokes some confusion, so here are the facts you should know:
- If you install a new HDD into a Windows XP system (or install a new OS onto the HDD) and want to create only one partition on it, you can use either the jumper or WD Align.
- The conditions being the same, but you want to create two or more partitions, Western Digital recommends using WD Align only. Our practice suggests that the jumper will also align two partitions but there is a possibility of the second partition remaining unaligned.
- If you open a disk image with partitions that contain data, you must use WD Align after that.
- If you are formatting your HDD in Windows Vista or Windows 7, you don’t have to do anything! Neither WD Align nor the jumper will be necessary then.
A small note: WD Align has a protection mechanism and will not allow you to align a partition if that is not necessary. So if you have any doubts, use WD Align and forget about the jumper. Do not insert the jumper after WD Align has aligned the drive (or refused to do so because the HDD is all right under Windows Vista/7).
The firmware versions of the tested HDDs are listed in the next table:
You should keep it in mind that the same models of HDDs may perform differently with other firmware.