by Aleksey Meyev
04/02/2007 | 01:58 PM
It is increasingly more important to be able to move from one PC to another or carry around large amounts of information. Software distributions and portable program versions which don’t require installation, data backups and video files – all this calls for a capacious but physically small storage medium. USB flash drives may prove to have too low capacities for that purpose and we have to switch to external hard disk drives.
Some people can be satisfied with storage capacities provided by 1.8” disks and others are ready to sacrifice compactness for the sake of capacity and prefer 3.5” devices, yet it is 2.5” models that are most popular among external hard disk drives. Somewhat longer but thinner than a common cigarette pack, a 2.5” HDD currently provides as much storage as hard disks in low-end PCs and can meet users’ storage requirements easily.
Three such HDDs with a capacity of 120GB will be discussed in this review.
This is in fact one and the same model from a noname manufacturer with different interfaces: one employs the common USB 2.0 while the other uses the less widespread FireWire (IEEE1394). Inside there is a 120GB hard disk drive from Samsung. This is a pure DIY solution, that is why it would be interesting to see if it proves any better than the ready products. Also, we’ll see if there’s any difference between these two interfaces when it comes to external HDD performance.
Otherwise, these devices are designed like many others of their kind: a plain-looking gray box with interface and power connectors. The additional power connector should be used on a PC that cannot provide enough power to the hard disk through one USB port.
These are the accessories you receive with the device: a CD with drivers and electronic user manual, an interface cable, and an additional power cable.
This is the TS120GSJ25S model from Transcend’s StoreJet series. This brand is well recognized on the market of compact storage media, but mostly due to the company’s flash drives and memory cards which have been regularly reviewed on our website, too. This HDD differs from the previous ones in shape and color only. It has a matte surface, too, and the same set of connectors on a side panel.
You get a soft pouch with a tie to carry the drive around. It is a nice accessory for those who want to keep their external HDD clean and tidy.
Western Digital manufactures hard disk drives only and has been quite successful at that. This is its Passport WD1200U017-002 model. The device looks cool with its shiny surface visible through the plastic package. This attractive surface may disappoint you somewhat afterwards. It is scratchable and will soon be covered with a web of microscopic scratches. It also gets soiled easily and your fingerprints will be just too visible on it. A soft pouch would come in handy here.
The connectors on the butt end pf the device are closed with a rubber plug which is firmly attached to the case. You shouldn’t worry it will get torn off accidentally.
When you connect this drive to a PC, you’ll find it to contain the WD Sync software. Following a Wizard with a user-friendly interface, you can copy files to the disk, and these files will be encrypted with the 128-bit AES algorithm. When synchronizing to the disk, you can create a protected copy of the Web-browser’s bookmarks and MS Outlook information like contacts, notes and calendar. These data will all be stored on the disk in encrypted form and will only be accessible after entering a password in the WD Sync window. This is a handy and practical solution for always having your confidential information with you. People who are constantly moving between several work places will surely appreciate this feature. But if you don’t want all this protection, you can just copy files to the disk without using this software.
Besides that, the HDD contains the WD Diagnostic Tool for checking the health of your hard disks, three programs from Google (Picasa, Google Toolbar, and Google Desktop Search), the indispensable Adobe Reader, and a short user manual. You don’t receive a CD with this software pack, so you may want to make a backup copy of it for yourself.
The drive comes with a short manual and a USB cable.
The following testing utilities were used:
We installed the generic OS drivers for the drives and formatted them in FAT32 and NTFS as one partition with the default cluster size. For some tests 32GB partitions were created on the drives and formatted in FAT32 and NTFS with the default cluster size, too.
IOMeter is sending a stream of read and write requests with a request queue depth of 4. The size of the requested data block is changed each minute, so that we could see the dependence of the drive’s sequential read/write speed on the size of the data block.
The HD-227FW with a FireWire interface delivers unrivalled performance irrespective of the data chunk size. Its max speed is 37.74MB/s on 128MB and larger blocks. Although the USB 2.0 interface has a higher theoretical bandwidth than IEEE1394a (60MB/s against 50MB/s), it has no advantage in practical applications. Compare the two brothers with different interfaces: the FireWire model is faster than its USB counterpart by one third on average. The WD Passport is the fastest of the models with a USB interface, providing a speed of almost 30MB/s when reading 64KB and larger data blocks.
It’s no different with sequential writing: the HD-227FW is still an overall leader while the WD Passport is ahead among the USB-interfaced devices. The WD drive acts up somewhat, however. It is even ahead of the FireWire drive on 64KB data blocks but just refuses to process 1024KB blocks, suffering a fivefold performance hit!
It is these sequential IOMeter patterns that are most important for mobile storage media because such media are mostly used exactly for sequential reading or writing whereas operation modes simulated by patterns like Database, File-Server or Web-Server are less likely to happen to an external HDD. We use the latter patterns to explore the theoretical capabilities of an external HDD.
In the Database pattern the drive is processing a stream of requests to read and write 8KB random-address data blocks. The ratio of read to write requests is changing from 0% to 100% throughout the test.
We built three diagrams for different request queue depths to illustrate performance of the HDDs in this test.
At a request queue of 1 the HDDs all begin at the same speed in the random read mode, but the HD-227U2 gains the lead when there are more writes to be performed. It is followed by its brother that concedes second place to the Transcend at 100% write requests only. The external HDD from Western Digital takes no part in this competition, being firmly seated at the bottom of the diagram.
The request queue depth is increased to 16 outstanding requests, but there are no changes in the HDDs’ standings: the HD-227U2 is the leader while the WD Passport is the loser. The Transcend seems to have problems when the queue contains 20-30% of write requests.
But now it’s hard to name the winner. The Transcend StoreJet wins in the random read mode, but then the two brothers with different interfaces take the lead. The StoreJet regains its leadership when there are more writes than reads in the queue. The WD still doesn’t take any part in the competition for the podium.
These patterns simulate the load typical of the disk subsystem of File and Web servers. The drive’s performance rating is calculated in this test by averaging its speed at request queue depths of 1, 4, 16 and 64.
When working in file-server mode, the two HD-227 models share top place with similar results. The WD Passport is the worst one here.
The four drives have similar performance ratings, the Transcend being just a little better than the others. Looking up in the table, you can see that it owes its high rating to its high speed at long request queue depths.
The Workstation pattern simulates the typical load on a workstation at request queue depths up to 32. This test was performed on the full capacity of the drives as well as on a 32GB partition created on them.
To calculate the overall performance rating of a drive in this test, we use the following formula:
Performance = Total I/O (queue=1)/1 + Total I/O (queue=2)/2 + Total I/O (queue=4)/4 + Total I/O (queue=8)/8 + Total I/O (queue=16)/16 + Total I/O (queue=32)/32.
The HD-227U2 wins this test, outperforming its opponents greatly at small request queue depths. The HDD from Western Digital finds itself occupying the bottom place again. This device seems to have been optimized for sequential reading and writing only.
The speeds are higher when we limit the address space to 32GB. The HD-227U2 leaves first place to its FireWire-interfaced mate. The WD Passport is the last one again.
The multi-threaded tests simulate a situation when there are several (from one to four) clients accessing the drive at the same time. The depth of the outgoing request queue is varied from 1 to 8. We’ll discuss diagrams for a request queue of 1, as most representative of real-life operation modes.
The sleeping volcano has woken up, sensing an operation mode common for external HDDs. The WD Passport lets the FireWire-interfaced model win only one subtest (with a single thread). In the other cases the Password is on top. The HD-227U2 is the worst drive here.
The Western Digital is not so good at writing. Taking first place in the single-thread subtest, it retires to last position, leaving the lead to the HD-227FW which confirms again that its interface is better, although less widespread, than USB 2.0.
First, you can have a look at the surface read speed graphs of the three testing participants:
The difference between the interfaces can be clearly seen here. The data-transfer graph of the HD-227FW has a very short horizontal stretch which goes at 37MB/s whereas all the USB models have a horizontal stretch at 30MB/s and its length is over 70GB, i.e. over half of the disk storage capacity. This horizontal stretch is the result of the data-transfer rate being limited by the interface the disk is connected to the PC with.
Now let’s check out 32GB partitions formatted in FAT32.
The USB models perform similarly, and the Transcend wins only through having a slightly better result in the High-End Disk Winmark subtest. The HD-227FW proves to be the slowest one here, especially in Business Disk Winmark. So, the interface alone cannot win everything, although I can hardly imagine a programmer who would use an external disk as the main one, and it is the programming test (the last in the table) that the FireWire-interfaced drive failed completely.
The HD-227FW looks hopeless in NTFS while its USB counterpart takes first place.
But the FireWire model has no rivals with its data-transfer rate, especially at the end of the disk. The Transcend cannot overcome the 30,000KB/s mark as the others do.
The WD Passport and the HD-227FW have the best access time among the tested devices, while the Transcend StoreJet has the worst result. The difference is a mere 0.4 milliseconds, though.
Now we will check performance of the hard disk drives with the FC-Test utility. Two 32GB partitions are created on the drives and formatted in NTFS and then in FAT32. After that a file-set is created of the hard disk. It is then read from the disk, copied within the same partition and then copied into another partition. The time taken to perform these operations is measured and the speed of the drive is calculated.
To remind you, the Windows and Programs file-sets consist of a large number of small files whereas the other three patterns (ISO, MP3, and Install) include a few large files each.
We’ll discuss the FAT32 results first.
The FireWire-interfaced disk is on top when creating files of any of the file-sets. Its USB-interfaced mate is following it closely. The Western Digital finds itself in last position in four out of the five file-sets.
When it comes to reading, the leader doesn’t change, but its USB mate takes last place in four out of the five file-sets. The drive from Transcend is the best one among products with a USB interface here.
Whatever the operation type, the drive with a FireWire interface still keeps ahead of its opponents. The HD-227U2 is the best one among the USB-interfaced products whereas the Transcend StoreJet is a loser here with every file-set.
Copying from one partition to another produces no different results. We’ve got the same leaders and losers as in the previous test.
The change of the file system somewhat enlivens our testing which has threatened to become one long glorification of the IEEE1394a interface. The HDD with this interface is still ahead of the others when processing large files, but loses to the HD-227U2 on smaller files. In a similar manner the drive from Western Digital leaves last place to the Transcend in the Windows and Programs patterns.
The HD-227FW regains its absolute leadership when reading the file-sets in NTFS. The Transcend StoreJet is second best in four out of the five patterns. The HD-227U2 and the WD Passport are slowest with large and small files, respectively.
When copying within the same partition the HD-227U2 is just a little better with small files than its FireWire mate. The Transcend takes last place in four out of the five file-sets.
Like with FAT32, the drives’ standings do not change when we switch from copying within the same partition to copying into another partition.
2.5” hard disk drives have progressed to the point when the USB interface bandwidth proves to be barely enough to allow them working at their highest speeds. Our comparison of the HD-227FW and the HD-227U2 has shown that the drive with a FireWire (IEEE1394a) interface delivers higher speed than its USB counterpart. The USB is by far more widespread, though. If you purchase an external HDD with a FireWire interface you may find yourself unable to connect to a PC just because it lacks a FireWire port. You should be also aware of the emerging external interface eSATA which provides an even higher data-transfer rate. We’ll discuss it in some other article.
Our tests have also shown that although the USB is close to being a bottleneck for an external HDD, the characteristics of the hard disk itself matter, too. We hope our reviews will help make your search for the highest-performance external 2.5” HDD easier.