Roundup: Hard Disk Drives with 640GB Storage Capacity

Today we are going to discuss the performance of five hard disk drives from Samsung, Seagate and Western Digital that feature 640GB storage capacity.

by Aleksey Meyev
03/06/2009 | 05:29 PM

We have tested hard disk drives with a capacity of 1 terabyte and three quarters of a terabyte (750GB), and now it’s time to move one step lower, to 640GB devices. This capacity may look odd because the manufacturers usually try to arrive at some round and nice-looking number. The explanation is simple: every 640GB hard disk drive is based on two latest-generation platters with a recording density of 320GB per platter. That’s why 1-terabyte drives use a three-platter design. But it should be noted that 1-terabyte drives have 333GB platters. The manufacturers must have reduced the capacity of each platter to 320GB in order to avoid the sinister number of 666 gigabytes. 640 gigabytes, on its part, is a logical continuation of the capacity growth from 160 through 320 to 640 gigabytes.


Dual-platter HDDs have always had an ambiguous standing. They are not remembered as “the world’s first to achieve the capacity of so many gigabytes” but still enjoy well-deserved popularity. It is dual-platter drives that used to have the lowest data storage cost per gigabyte. They have only been outdone recently after the considerable price cut on 1-terabyte models. You can also expect very good performance from them: each of the five HDDs included into this review is based on full-size 320GB platters whereas there can be drives with lower recoding density among 500GB and 750GB models. Well, it is going to be interesting to compare them!

Testing Participants

Samsung SpinPoint F1 DT, 640GB: HD642JJ

The SpinPoint F1 series provoked a kind of sensation on the HDD market. It is within this series that the world’s first 333GB-platter drives came out (those were 1TB rather than 640GB models). Thanks to it, Samsung successfully enlarged its share of the HDD market and left the group of the lagging brands (Samsung’s HDDs had been inferior to their opponents in maximum capacity). Recently the company’s product range has been complemented with enterprise and economical HDD series, and the desktop series has acquired a small addition to its name. It is now called SpinPoint F1 DT.

Seagate Barracuda 7200.11, 640GB: ST3640323AS

Seagate modernized its Barracuda 7200.11 series at a certain moment, adding 320GB-platter drives into it (the series had been originally based on 250GB platters). This made things more complicated for users looking for highest-performance HDDs because Barracuda 7200.11 drives of the same capacity but with different platters were selling simultaneously. The problem affected the models with capacities of 500, 750 and 1000GB.

Seagate didn’t stop at that, though. Later on, the company introduced a model with an even higher recording density, 375GB per platter, into the Barracuda 7200.11 series. Why? Just to be ahead of its competitors in releasing the world’s first 1.5-terabyte drive (ST31500341AS). The combination of four-platter design and then-densest 375GB platters ensured a tactical win for Seagate.

Unfortunately, this is not going to be the most memorable fact about the series. In mid-January we learned that there was a serious error in the firmware (all firmware versions save for the latest SD2*, CC** and LC**) of all HDDs of the series as well as of the similar ES.2 and Seagate-Maxtor DiamondMax 22 series. Because of that error a fully functional drive would not be identified at all or identified with a capacity of 0 gigabyte at startup. The drive’s data were not destroyed, but you had to go to a service center to read them. After mass media and Seagate forum users had made a racket, the company acknowledged the problem officially and posted firmware updates at its site (by the way, this is only a second case in Seagate’s history when firmware is made officially available for download). So, if you’ve got a drive belonging to this series, we recommend you to visit the acknowledgement link, download the software that identifies your HDD firmware and, if necessary, update the latter. Of course, the problem may pass you by (our sample of the HDD has the problematic firmware, but works normally as yet), but why risk your data?

Western Digital Caviar Green, 640GB: WD6400AACS

Released in 2008, Western Digital’s Green series is dramatically different from the others on one point: it has the mysterious word IntelliPower written in its specs against the spindle rotation speed entry. These HDDs had been supposed to vary the speed by lowering it from 7200rpm under load to 5400rpm in idle mode to save power but so far every test suggests that they just have a spindle rotation speed of 5400rpm without any variations. Besides, this series features economical electronics as we will discuss in an appropriate section. Can such products have any market success? Yes. If you are assembling a NAS or want to install a disk into an external storage device, you don’t need maximum performance whereas low power consumption, low temperature and reduced noise are most welcome. Samsung offers a similar series called EcoGreen, but Western Digital’s Green drives are more widespread as yet.

Western Digital Caviar Blue, 640GB: WD6400AAKS

The HDDs of the Western Digital Caviar Blue series were made by simple renaming. They had used to be called Caviar SE16. One of the early drives, produced before the series was renamed, is shown in the photo above. Later models got a different label that is designed to resemble the new series but is blue, of course. The label is the only change, though. The contents of the HDD case are the same. By the way, this model was the world’s first 640GB drive to begin selling in shops.

Western Digital Caviar Black, 640GB: WD6401AALS

Yet another drive from Western Digital, this one belongs to the high-performance Caviar Black series. Every disk of this series boasts 32 megabytes of cache memory and the Dual Processor feature. The point of the latter is explained rather vaguely at the company’s website – “Twice the processing power to maximize performance.” So, we don’t know if the HDD just has faster electronics or is really equipped with two independent processing cores. Anyway, we can expect more from the Black than from the Blue series.

The following table lists the specs and firmware versions of the tested devices.

There are a few things we should note here. First, not only the WD Caviar Black but also the Seagate Barracuda 7200.11 is equipped with 32 megabytes of cache memory, so we can expect high performance from that HDD. Second, Western Digital has stopped to declare the average seek time parameter in its drives’ specs but specifies a drive ready time. And third, Western Digital has the same firmware for both the Blue and Black models. The difference between them will obviously depend on the amount of cache memory and the mysterious Dual Processor feature.

Testbed and Methods

The following testing utilities were used:

Testbed configuration:

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. In every test, save for IOMark and the Defragmentation test, the drives were connected to a Promise SATA300 TX4302 controller installed into a PCI-X slot and had their NCQ support enabled.

Performance in IOMark

We use our internal IOMark tool for low-level tests. Let’s check out the sequential read speed of the drives first.

Now we can compare the HDDs by the read speed at the beginning and end of the partitions created on them.

Judging by the graphs, the manufacturers all try to squeeze everything out of the drives: the speed is considerably higher with lucky surface/head combinations and the graphs are not smooth but fluctuating. The resulting diagram does not represent the situation correctly because the numbers depends greatly on whether the HDD has a lucky surface/head combination at the beginning and end. The only thing we are sure of is that the Seagate is faster than the others. The Caviar Green is expectedly slower than the HDDs with higher spindle rotation speed, the difference amounting to about 30MBps.

And what about buffer memory? We will check this out using a test that reads and writes data in small blocks that fit entirely into the cache buffer.


The HDDs are all about the same with data blocks up to 128KB, delivering speeds above 200MBps at both reading and writing, the Samsung and Seagate being somewhat faster than the drives from Western Digital. The picture is more interesting when you take a look at the graphs. When the data block is larger than 128KB (256 sectors), Western Digital’s drives have a temporary reduction of speed, but then their burst read speed begins to increase. The speed of writing doesn’t increase and shows rather odd fluctuations. The Samsung is neater and smoother: it suffers the same performance hit and delivers normal speed of writing. The Seagate has uniform speed but its performance hit is heavier: the burst read speed returns to the level of 170MBps while the burst write speed is barely above 100MBps when the drive is processing large data blocks.

Performance in Intel IOMeter

Sequential Read & Write Patterns

From the low-level IOMark to the synthetic IOMeter. 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. This test is indicative of the maximum speed the drive can achieve.

The numeric data can be viewed in tables. We’ll discuss graphs and diagrams.

IOMeter: Sequential Read results

Seagate’s drives often boast a superb speed of sequential reading, and this test session is no exception. The Seagate takes first place, notching a speed of 118MBps. The opponents are 10MBps and more behind. Interestingly, the Black model from Western Digital is somewhat slower than its Blue mate. The Samsung has a good top speed but reaches it at larger data blocks than the opponents. Moreover, it is noticeably slower with small data blocks. The WD Caviar Green is not very fast because of its reduced spindle rotation speed.

IOMeter: Sequential Write results

The Seagate is in the lead at writing, too. The Caviar Black is still somewhat slower than the Caviar Blue. The Samsung loses its speed for some reason and is no faster than the Caviar Green even with large data blocks.

Disk Response Time

In this test IOMeter is sending a stream of requests to read and write 512-byte data blocks with a request queue of 1 for 10 minutes. The total number of requests processed by the HDD is over 60 thousand, so we get a sustained response time that doesn’t depend on the HDD’s buffer size.

The Western Digital Caviar Black has the best response time at reading, being just a fraction of a millisecond better than its Blue opponent. This pair looks good in this test. The Seagate and Samsung are more than 1 millisecond behind. The 5400rpm drive is lagging behind. It is about 1 millisecond worse than the closest opponent and more than 2 milliseconds worse than the leader.

The Samsung is the best drive at writing. It is followed by WD’s Caviar Black and Caviar Blue drives that have similar results. The Green drive from WD is only 1 millisecond worse than its mates because write requests are saved into the drive’s cache. The Seagate’s result of 30 milliseconds is quite a shock. Such a high value could be explained by the drive’s doing write verification (by reading data it has written to check its integrity), but this technology would only be enabled in harsh thermal conditions or at strong vibration. We have our drives working in very comfortable conditions with effective cooling, so there is no need for additional self-control. We just can’t understand the odd behavior of the Seagate Barracuda 7200.11.

Random Read & Write Patterns

Now we’ll see the dependence between the drives’ performance in random read and write modes on the size of the data block size.

We will discuss the results of the disk subsystems at processing random-address data in two versions. For small-size data chunks we will draw graphs showing the dependence of the amount of operations per second on the data chunk size. For large chunks we will compare performance depending on data-transfer rate in megabytes per second. This approach helps us evaluate the disk subsystem’s performance in two typical scenarios: working with small data chunks is typical for databases. The amount of operations per second is more important than sheer speed then. Working with large data blocks is nearly the same as working with small files, and the traditional measurement of speed in megabytes per second becomes more relevant.

Let’s start with reading.

IOMeter: Random Read, operations per second

There are three groups of drives in the random read test. The leading group includes the Blue and the Black models from Western Digital. Judging by the similar results, the actuators of these two models are equally quick. The Seagate and Samsung with similar performance are in the second group. The 5400rpm Green model from Western Digital takes last place. The nice-looking neat graphs are only spoiled by the sudden slump of the Seagate on 128KB data blocks, reminding us of the slump in its sequential reading graph. This effect seems to occur on 128KB data blocks rather than after them.

IOMeter: Random Read, MBps

All of the drives, save for the WD Caviar Green, go close to each other. The Samsung is just a little slower than the others, probably because of its lower sequential read speed. The data blocks are large here, after all.

IOMeter: Random Write, operations per second

When writing in small data blocks, we can see the consequence of the Seagate Barracuda 7200.11 having shown a poor write response time. It processor seems to be unable to cope with the numerous small-size random-address data chunks while doing deferred writing. That’s sad because Windows processes system registry and many other system data in 512-byte blocks. As for the other HDDs, the Samsung is noticeably faster than the pair of Western Digital drives which have identical results again. The Black model doesn’t show its superiority as yet.

IOMeter: Random Write, MBps

The Seagate is all right when writing large data blocks. It is even occasionally in the lead. The HDDs are close to each other again, excepting the WD Caviar Green.

Database Patterns

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% with a step of 10% throughout the test while the request queue depth varies from 1 to 256.

You can click the following link to view the tabled results: IOMeter Database table.

We will build diagrams for request queue depths of 1, 16 and 256.

Request reordering is impossible at the minimum queue depth. The speed of the heads and deferred writing are the only two factors a drive’s performance depends on here. The Blue and the Black models from Western Digital are still ahead of the others at reading, but give way to the Samsung and Seagate when write requests prevail. The Samsung is the faster drive in this pair: the Seagate only outperforms it at pure reading. The WD Caviar Green is surprisingly good. It is quite competitive at high percentages of reads. By the way, its graph has almost the same shape as the graphs of the other HDDs from WD. They seem to share the same firmware algorithms.

The queue is now 16 requests deep. Let’s see how the performance of the drives increases. The standings do not differ much: the HDDs from Western Digital are still in the lead but give way to their opponents at high percentages of writes. The Samsung is somewhat better than the Seagate at writing but worse at reading. The Seagate must be equipped with more efficient NCQ algorithms. The WD Caviar Green is almost as fast as the Samsung at reading. That’s an excellent performance for a HDD that has a lower spindle rotation speed than the others. Interestingly, the Green one has more effective deferred writing than the Blue and the Black models.

When the queue is even longer, we can see all the things we’ve seen above plus a few more facts. For example, the Caviar Black breaks away from the Caviar Blue at reading: its double processing power seems to come into effect. The Seagate is ahead of the Samsung at every load, including writing. This must be due to its larger cache buffer. The Samsung has minor flaws in its firmware for some reason that lead to a sudden performance hit at 10% writes.

To sum up this section of the review we’ll publish the drives’ graphs for five queue depths.

The Samsung behaves just like the other SpinPoint F1 series models we have seen before. NCQ is here and even more effective than in the firmware of Samsung’s earlier series. Deferred writing can be observed, too.

It is a most fascinating thing to watch Seagate’s firmware evolve. And as the recent story shows, sometimes you’d better watch this process from the outside. Here, we can see that the progress has reached a certain limit already. The drive has request reordering and good deferred writing. There are no problematic sections in the graph. But judging by the test results, this firmware can still be improved to the level of Western Digital’s products at least.

Western Digital seems to have developed a single basis for all its firmware. The company’s latest drives (even 2.5-inch ones) all come with firmware that shows the same behavior. And there is no problem in that: the firmware is good indeed, especially in terms of request reordering. Deferred writing might be better, though. The present implementation of this technique is not very effective.

Web-Server, Fileserver and Workstation Patterns

The drives are tested under loads typical of servers and workstations.

The names of the patterns are self-explanatory. The Workstation pattern is used with the full capacity of the drive as well as with a 32GB partition. The request queue is limited to 32 requests in the Workstation pattern.

The results are presented as performance ratings. For the File-Server and Web-Server patterns the performance rating is the average speed of the drive under every load. For the Workstation pattern we use the following formula:

Rating (Workstation) = 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.

Quick heads and excellent NCQ algorithms ensure Western Digital’s 7200rpm drives a confident win in this test that includes read requests only. The Samsung and Seagate are competing fiercely: the former is better at short queue depths and the latter, at long queue depths. Let’s see what ratings the HDDs have.

The Seagate Barracuda 7200.11 enjoys a smallest advantage in terms of ratings. By the way, the results of the Western Digital drives are the best among all the HDDs we have ever tested. The performance of the Seagate and Samsung is somewhat better than average while the 5400rpm Caviar Green is inferior to almost every 7200rpm drive, save for those that have stopped selling due to low storage capacity. So, you should not use this HDD in reads-oriented RAID arrays.

Reads are laced with 20% writes in the File-Server pattern. This has no effect on the standing of the pair of Western Digital’s drives which stay in the lead. The Caviar Green has got closer to the Samsung, though.

Despite the complex situation in the area of low loads the Seagate is faster than the Samsung and the latter is somewhat better than the WD Caviar Green.

The Samsung is the best drive under the Workstation load. It is closely followed by the pair of Western Digital drives. The Seagate is poor in this test, especially at low loads. Its 32 megabytes of cache memory don’t help it at all.

The ratings agree with what we’ve seen in the diagram.

When the test zone is greatly limited (32GB is a mere 5% of the total capacity), the 7200rpm drives go very close to each other, the Samsung falling behind at high loads only. The Caviar Green is still very slow. Take note that the speeds are about 50% higher when the drives work with the fastest zones of their platters. Do not forget about that because you can allot your OS the fastest part of the hard disk during installation and give out the rest for a second partition with data.

According to our ratings, the Seagate Barracuda 7200.11 wins this test.

Multithreaded Read & Write Patterns

The multithreaded tests simulate a situation when there are one to four clients accessing the virtual disk at the same time, the request queue depth varying from 1 to 8. The clients’ address zones do not overlap. We’ll discuss diagrams for a request queue of 1 as the most illustrative ones. When the queue is 2 or more requests long, the speed doesn’t depend much on the number of applications. You can also click the following links for the full results:

The Seagate loses its lead in terms of sequential speed as soon as we add a second data thread. The WD Caviar Blue goes ahead then. Having the same firmware, the Caviar Black has lower results for some reason. Perhaps it is a negative effect from its Dual-Processor electronics? Whatever the reason, it is even slower than the Caviar Green. The latter is very good, staying in second place at multiple threads.

The Samsung is a disappointment. Such low performance as it provides used to be a characteristic feature of Seagate’s products, but Seagate has solved that problem by now. Now it is the second drive from Samsung that looks poor in this test (the first one was the 750GB model of the SpinPoint F1 series). We wouldn’t like this performance to be a typical trait of the whole series. And we have some hope because the 1-terabyte model was quite good at multithreaded reading.

But it is the Samsung that copes best with multithreaded writing. The WD Caviar Blue is competing with it at two threads, but the Samsung is the single leader when it comes to handling more data threads. The Seagate is not good here: its speed drops to the level of the WD Caviar Green at multiple threads although it has a 50% higher speed than the latter at one thread.

Performance in FC-Test

For this test two 32GB partitions are created on the disk and formatted in NTFS and then in FAT32. After that a file-set is created. 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 disk is calculated. 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’d like to note that the copying test is indicative of the drive’s behavior under complex load. In fact, the HDD is working with two asynchronous threads (one for reading and one for writing) when copying files.

We will only discuss the NTFS data because the standings are generally the same in FAT32. You can use the links below to view the full results: FC-Test FAT32 table.

The WD Caviar Black is far better than the others at creating files. It is faster than the second-best Caviar Blue with very file-set. Oddly enough, it is the WD Caviar Green rather than the Seagate that competes with the Samsung for third place. The Seagate has surprisingly low results in this test and finds itself in last place.

We see the Caviar Black in first place and the Caviar Blue in second at reading, too. The only difference is the ISO pattern with very large files where the Seagate goes ahead. The Seagate is only fourth with the three other file-sets and even fifth with the Windows file-set.

We’ve got the same leading trio (two drives from Western Digital plus the Samsung) in the two copying tests: within one partition and between two partitions. The only difference between the results of these two tests is the performance of the Seagate that is competing with the WD Caviar Green more or less successfully. When copying within one partition, the Seagate wins in the Install and MP3 patterns by a small margin but is far slower in the ISO pattern (and the leading HDD is almost 50% faster having platters with the same characteristics). When copying from one partition to another, the Seagate wins in the MP3 pattern only. That’s a poor performance.

Performance in PCMark 2004

PCMark04 benchmarks drives in four different modes: Windows XP Startup is the typical disk subsystem load at system startup; Application Loading is the disk activity at sequential starting-up and closing of six popular applications; File Copying measures the HDD performance when copying a set of files; the General Usage parameter reflects the disk activity in a number of popular applications. These four parameters are used to calculate the overall performance rating.

We ran each test ten times and averaged the results.

Western Digital’s sweet pair takes the two top places in the Windows XP loading test. Well, this is no wonder after the results of the synthetic benchmarks. The Caviar Blue is somewhat ahead of its partner.

We’ve got the same leaders at loading applications. They have increased the gap from the pursuers and differ more from each other.

Copying files produces the same results as the FC-Test, the Caviar Green being considerably faster than the Seagate 7200.11. So, this is not just a peculiarity of one specific benchmark.

There are no changes among the leaders in the General Usage test. The pair of Western Digital drives is going to pass this test in the same positions.

It is quite logical that the WD Caviar Black has first place. The Caviar Blue is second and quite far behind the leader. The Samsung is third. The Seagate has a very low result. Being much slower than the leaders, it is about as slow as the WD Caviar Green that has last place.

Performance in PCMark 2005

PCMark05 is an updated version of the previous benchmark. Instead of File Copying, there is now a File Write trace. A new trace called Virus Scan is added. Its name is self-explanatory.

Again, we performed each test ten times and averaged the results.

The leaders of these three tests are the same as in the previous version of the benchmark: two drives from Western Digital.

The leaders do not change in the new Virus Scan test, either. The difference is that the Caviar Green is now third, outperforming both the Seagate and Samsung. That’s the better firmware for you!

The standings change more in the File Write test. The WD Caviar Blue is first while the Caviar Black is third. The Seagate 7200.11 takes second place, delivering a speed of over 100MBps. Perhaps this drive’s firmware conflicted with the somewhat unrealistic load in FC-Test, yet this is still an indication of some imperfectness in firmware.

Combining its Dual Processor feature, 32MB of buffer memory and good firmware, the WD Caviar Black wins one more test. The WD Caviar Blue is second, and the Seagate is third.

Performance in PCMark Vantage

To make this part of our test session complete, we are going to run the latest version of PCMark called Vantage. Compared with the previous versions, the benchmark has become more up-to-date and advanced in its selection of subtests as well as Windows Vista orientation. Each subtest is run ten times and the results of the ten runs are averaged.

Here is a brief description of each subtest:

Basing on these subtests, the drive’s overall performance rating is calculated.

We’ve got a new OS and a different load but the two drives from Western Digital do not want to leave the top of the podium. The Seagate takes third place now.

The two HDDs from Western Digital do not differ in terms of gaming performance. Both are good for games. The Seagate is far better than the Samsung which in its turn is but slightly better than the 5400rpm WD Caviar Green.

The WD Caviar Black is just what you need for managing photo galleries. The WD Caviar Blue is worse and comparable to the Seagate 7200.11. The Samsung F1 is no good in this test, being about as slow as the WD Caviar Green.

Western Digital’s Blue and Black drives cope better with booting the OS up than the others even if it is Windows Vista rather than XP. The Samsung shows the worst result for some reason.

We’ve got the same standings in the Movie Maker test. The Samsung’s firmware seems not to line the changes in the file processing mechanisms that occurred with the transition from Windows XP to Vista.

The tests change but the standings do not. The Media Center test produces the same picture as the previous tests.

The Samsung drive takes third place in the Media Player test. It should be noted that the Samsung, Seagate and WD Caviar Green have similar results, which is good for the latter model that is the quietest and most economical among the three.

The HDDs pass the Application Loading test just like in the previous versions of the benchmark. The only difference is that the Caviar Blue is almost as fast as the Caviar Black.

The final scores put the Caviar Black and Caviar Blue in first and second places, while the Samsung is barely ahead of the WD Caviar Green. This generation of Western Digital’s drives is obviously superior to their opponents.


Next goes our homemade test of defragmentation speed. We created a very defragmented file system on a 32GB partition of a hard disk by loading it with music, video, games and applications. Then we saved a per-sector copy of the disk and now copy it to the HDD we want to test. The tested HDD is connected to the mainboard’s SATA controller whose operation mode (AHCI/Standard IDE) is controlled from the mainboard’s BIOS. Next we run a script that evokes the console version of the Perfect Disk 8.0 defragmenter and marks the time of the beginning and end of the defragmentation process.

Thus, each HDD is tested twice: with the controller’s AHCI support enabled and disabled. You can refer to a dedicated article for details about this test.

Western Digital’s drives take the two top places in this test, too. The Blue model is a quarter of a second faster than the Black one. The Samsung is somewhat slower, and the performance of the WD Caviar Green looks normal. It is the Seagate that took too much time to do the defragmentation – over half an hour. Interestingly, the test was performed slower with enabled NCQ only on the Seagate drive. It probably didn’t like the change of the mainboard’s SATA controller driver in the NCQ-enabled mode.

Power Consumption

You can refer to our Hard Disk Drive Power Consumption Measurements: X-bit’s Methodology Indepth for details on this test. We’ll just list the specific modes we measure the power consumption in:

Let’s check out each mode one by one. We are especially interested in how economical the WD Caviar Green is in comparison with the other HDDs.

Well, the Caviar Green is indeed different from the others even during startup. Its electronics consumes about the same amount of power (the 5V line) as those of the opponent drives, but its mechanism needs but half the current required by the other HDDs among which the Samsung is the best. The Seagate shows itself as the most power-demanding device.

The WD Caviar Green is about twice more economical than the other HDDs. Besides consuming less power to rotate the spindle, which might be expected, it also boasts the lowest consumption of the electronics. As a result, it only consumes half as much as the other HDDs. According to the laws of physics, it dissipates two times less heat and has lower cooling requirements.

There are two leaders among the ordinary HDDs: the Samsung has the lowest consumption of the electronics (which is still 0.5W higher than that of the Caviar Green) whereas the Seagate preferred to economize on the 12V line, i.e. on the mechanics. The Western Digital Caviar Black needs the most power of all – it seems to be always ready for work.

There is nothing to economize or optimize at random reading. This is the most power-consuming mode of operation. The drives have almost the same consumption of the electronics except that the Seagate 7200.11 has a lower consumption on the 5V line than the WD Caviar Green. We’d applaud it if it were not for the poor performance of the Seagate when reading small data blocks. We don’t think it is worth the minor power-related benefits. Moreover, the Seagate eats so much power from the 12V line that its combined power consumption is higher than that of every other HDD. As for the economical WD Caviar Green, it is not as good in this mode as when idle, yet requires far less power than the 7200rpm models.

Deferred writing helps every drive to lower the power consumption at random writing in comparison with random reading. The Seagate has a much lower consumption on the 12V line and lowers its 5V consumption, too. As a result, it is very close to the leader Caviar Green. The latter is still unrivalled in terms of 12V consumption but its electronics are hardly economical, requiring just a little less power than the other drives from WD but more than the Seagate or Samsung. The Western Digital Caviar Black is the most voracious drive under this load.

>From a power consumption standpoint, sequential reading is better than random reading because the HDDs do not have to move their heads much. The 12V consumption is lower as the consequence. The electronics requires more power, however, because it has to process more requests.

It is the Seagate that has the most economical mechanics among the 7200rpm models in this test. The HDDs from Western Digital are hungrier, especially the Dual-Processor Caviar Black. However, it is the Samsung that is the worst drive in this test. Its electronics consumes 0.5W more than that of any other drive, and its mechanics is not quite economical, either. No drive can challenge the Western Digital Caviar Green which has more economical electronics and, especially, mechanics.

And finally, we’ve got sequential writing.

Western Digital’s drives, including the Caviar Green, have higher 5V consumption than the others. Coupled with the voracious mechanics, this makes the Black model the loser of this test. The Seagate is the most economical among the ordinary drives but it is still no match to the Green model from Western Digital in terms of combined power consumption.


This test session has shown that there are different hard disks for everyone’s taste.

Do you want the fastest drive for a home computer? Take a Western Digital Caviar Black. This HDD is quite universal and looks good under server loads. It is actually free from serious downsides. Its high performance is accompanied with rather high power consumption, though. And some users may not like the clacking of its briskly heads.

Do you need the quietest and coolest drive? Consider the Western Digital Caviar Green. Its lower performance (by an average 20%) is made up for by lower power consumption and heat dissipation, and it is far superior to the 7200rpm models in terms of noisiness.

Do you need a drive for server loads but don’t want to pay for enterprise series models? The Western Digital Caviar Blue was the fastest in our server tests, outperforming its Black series counterpart even. Overall, it is as universal as the Caviar Black but its performance and power consumption are lower.

Do you need a truly universal drive that won’t demand special cooling? Choose between the Samsung SpinPoint F1 DT and the Seagate 7200.11. The latter is somewhat more economical and faster at sequential operations but has a number of flaws in its firmware starting with the risk of the drive not being identified after startup and ending with very poor writing of small data blocks. The Samsung has stable firmware and lower noise level but is slow at multithreaded reading.