Western Digital Scorpio Blue: WD5000BEVT-22ZAT0 – 500 GB
Here is one more representative of the 500GB generation, this time from Western Digital.
Western Digital Scorpio Blue: WD6400BEVT-00A0RT0 – 640 GB
The Scorpio Blue series progressed to 640 gigabytes as soon as 320GB platters had become available. Western Digital did not want to lose the race for high storage capacity.
Western Digital Scorpio Blue: WD6400BPVT-00HXZT0 – 640 GB
Then, unexpectedly, another 640GB model popped up in the Scorpio Blue series. The change of the second letter in the model name from E to P denotes a transition to 4KB formatting. Yes, it is the same Advanced Format technology we know from 3.5-inch drives.
The previous model began to leave the shelves quickly as if Western Digital focused all its production efforts on the new model. This must be due to a higher yield of platters with Advanced Format technology.
Western Digital Scorpio Blue: WD7500BPVT-22HXZT0 – 750 GB
The same series now includes a 750GB model with 8MB buffer. It features Advanced Format technology, too. Western Digital offered 750GB models before, but this one is based on only two platters whose recording density is as high as 376 gigabytes per platter. Other makers have announced similar products of their own, but this is the only dual-platter model of that capacity we have actually seen so far.
You may note that the new cycle of progress has not been as dramatic as before: the recording density used to grow in steps of 50% whereas the transition from 250 to 375 gigabytes has taken not one but two steps.
Advanced Format provoking a lot of questions and arguments, we will briefly repeat what we detailed in our first review of an HDD with that technology.
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 kilobytes 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 overall 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 for 4KB data blocks are 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 by means of the so-called alignment. With 3.5-inch drives, you can close pins 7 and 8 with a jumper to automatically shift the whole logical structure of the hard disk 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. 2.5-inch HDDs do not offer this choice: you have to use WD Align for them.
This alignment thing provokes some confusion, so here are the facts you should know if you’ve got a 2.5-inch drive with Advanced Format:
- If you install a new HDD into a Windows XP system (or install a new OS on the HDD), you need to align.
- If you open a disk image with partitions that contain data, you must use WD Align after that.
- If you format your HDD in Windows Vista or Windows 7, you don’t have to do anything! No alignment is required.
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 it will tell you what to do.
If you want to use a 2.5-inch HDD with Advanced Format in an external enclosure, Western Digital recommends that you first format the drive by connecting it to a mainboard’s SATA port. If you have Windows XP, you will have to run WD Align after that. If you have Windows Vista or 7, you can install the HDD into the external enclosure right after the formatting.
The next table shows the firmware versions of the HDDs we are going to benchmark today.
You should keep it in mind that the same models of HDDs may perform differently with other firmware.