by Aleksey Meyev , Nikita Nikolaichev
01/11/2010 | 02:53 PM
The world is often evolving in what looks like a spiral. Here is an example from the hard disk drive market: on the previous turn of the spiral we compared 2-terabyte models with spindle rotation speed of 5400rpm but now we are going to study products whose platters are rotating at a higher speed.
Using its time-tested 5-platter design, Hitachi was the first to introduce such a model, the Deskstar 7K2000, reminding us of the situation with 1-terabyte HDDs two years ago. Then, the 5-platter design coupled with lower-density platters helped Hitachi be two or three months ahead of its opponents and offer a 1TB drive that had no alternatives. The opponents eventually joined the race, though, and offered 1 terabyte on three platters only, and Hitachi’s only argument was a very low, nearly dumping, price afterwards.
Hitachi’s opponents, in their turn, focused on polishing off 500GB platters by releasing 1-platter slim 500GB products such as the Seagate ST3500410AS/ST3500318AS, Samsung HD502HJ, and WD WD5000AAKS-00V1A0. These drives are a different story and should be left for another review, though.
The manufacturers having achieved a stable operation of a pack of 500GB platters, 4-platter HDDs rushed to the market. All of the makers, excluding Samsung which is not yet ready to produce a 4-platter desktop HDD, have decided that a large HDD needs a large cache buffer. The amount of 64 megabytes of cache memory, first implemented by WD in its WD2002FYPS, has become a de-facto standard as all new-generation HDDs are equipped with it. Seagate even went further and equipped its Barracuda XT with a SATA 6Gbps controller. Sounds nice, but there are very few mainboards available that support the new SATA specification as yet. Moreover, the speed of reading from platters has not yet even approached the peak bandwidth of the SATA 3Gbps standard. So, we don’t quite get Seagate’s point. Is it an attempt to outperform its opponents or a purely marketing move? Western Digital, on its part, does not hurry with the interface. Let’s see whose approach proves to be better.
Hitachi did not take part in the first wave of 2-terabyte HDDs (those with a spindle rotation speed of 5400rpm and 5900rpm), but not to release 7200rpm products would hurt the company’s prestige too much. Therefore, the new Deskstar 7K2000 series was introduced. The word series is somewhat too loud here as it includes but one model as yet. On the other hand, the other makers do not introduce 1.5TB 7200rpm drives, either.
The design of this series is unique if compared to the opponents’ products, but traditional for Hitachi’s high-capacity HDDs. We’ve got five platters and ten heads here, again. And the question is if Hitachi used platters with a recording density lower than 500GB or just reduced the operating zone of each platter.
As usual, there is also a server-oriented Deskstar A7K2000 series which features a much lower rate of irrecoverable errors.
This model is already familiar to us from a previous review. It is the first drive from Seagate to achieve a capacity of 2 terabytes. And it is also the senior representative of the new Barracuda LP series which has a spindle rotation speed of 5900rpm. We include it in this review for the sake of comparison as a representative of the first generation of 2TB products.
Seagate seems to be kind of superstitious. The new series of 7200rpm Barracudas was named XT rather than 7200.13. The new-generation drives have the same 500GB platters as the 7200.12 series but as many as four of them! The new feature is a 64MB cache. Western Digital was the first maker to install so much cache memory into its RE4-GP and Seagate follows the suit. Memory is not so expensive today, after all. We will see in our tests what benefits the enlarged cache brings about.
This is not the only innovation, though. Seagate has implemented a new type of the interface, SATA 600 (together with the introduction of SAS 6Gbps in the Seagate Cheetah 15K.7, by the way). As you may guess, the new version is backwards-compatible with the earlier SATA but doubles the data-transfer rate to 600MBps. Such a high bandwidth won’t be necessary for hard disk drive for the time being because the speed of sequential reading of modern 7200rpm models is only approaching the bandwidth of the very first SATA standard (150MBps). Thus, the second version of the SATA interface offers a double reserve of bandwidth.
The interface bandwidth is more important for SSDs and disk racks. For them, 600MBps is going to come in handy, but we are talking about HDDs here. The only performance gain we may observe is the speed of data access in the 64MB cache.
We know this HDD, too: we have discussed it in our previous review. It was the first 2TB drive we managed to get and it is included into this review for the sake of comparison. By the way, this HDD has got a cousin with 32 rather than 64 megabytes of cache, called WD20EARS, but we don’t have it yet, unfortunately.
Earlier products from the Black series used to deliver excellent performance, so we were looking forward to testing a 2-terabyte Caviar Black. Finally, we can make it. This model is the best of all that Western Digital offers for desktop PCs. It is equipped with 64 megabytes of cache memory and this amount is going to become standard sooner or later.
The heads actuator of this HDD is special and composite. It uses a traditional electromechanical actuator for moving the heads at large angles (by the HDD’s standards, of course) and then adjusts the position of the head above the necessary track by means of a small piezoelectric actuator. It looks like working with very narrow tracks of 500GB platters is not a simple matter. Curiously, this technology is not new. This kind of an actuator was employed by some HDDs from now-defunct Maxtor.
As is often the case, the desktop model is accompanied with a server-oriented cousin. The new HDD series is called RE4 and has all the features of the Caviar Black but is additionally equipped with an acceleration sensor that protects the HDD against vibration.
Western Digital’s new HDDs, both Caviar Black and RE4, have one peculiarity. When turning off, the HDD is producing a very special sound (we’ve even tried to record it as best we could) we have not heard with any other HDD so far. We are not absolutely sure, but it looks like the HDD’s motor begins to rotate in the opposite direction to halt the platters faster.
The following table lists the specs and firmware versions of the tested HDDs:
Click to enlarge
The following testing utilities were used:
The HDDs were tested with the generic OS drivers. We 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. The HDDs were connected to a mainboard port and worked with enabled AHCI.
We’ve come to use the disk controller integrated into Intel’s ICH7 South Bridge because our recent tests showed that our beloved Promise controller had some bandwidth related problems. Of course, they do not show up with hard disk drives, but it is handier for us to have a single testbed for most types of storage devices (SAS drives do not count in due to obvious reasons). A brief examination proved that the ICH7 with new drivers is free from significant drawbacks. Moreover, this controller is the most widespread one (the newer versions do not differ from it as yet).
We will additionally test the Seagate Barracuda XT on the Marvell 9123 controller integrated into the ASUS P7P55D Premium mainboard. It is the single readily available SATA 600 controller right now. We just don’t have any other way to check out the performance of the new interface.
We use our internal IOMark tool for low-level tests. Let’s begin with sequential reading.
Let’s compare the drives according to the speed at the beginning and end of the full-capacity partitions created on them.
Everything is neat and logical here. Three out of the four newcomers have almost identical speeds, the Hitachi 7K2000 falling behind. The latter drive has a typical ratio of speed at the beginning and end (2:1), which makes us think that it uses five lower-density platters. This is sad as we’d be much more interested in platters with a reduced diameter. The lower recording density must have helped Hitachi cut the manufacturing cost (by slackening up the quality requirements) and this must be more important for the company than an advantage in speed.
And what about cache access? That’s an interesting subject as we’ve got a HDD with a new, higher-bandwidth, interface. Let’s take a close look at the results.
Hitachi Deskstar 7K2000: work with the buffer
Let’s begin with the Hitachi 7K2000. This drive’s graph is so much different from what its predecessors showed (for example, the Deskstar 7K1000) that we suspected something was wrong with our testbed. Yet the results are correct and Hitachi’s HDDs have indeed changed their behavior dramatically. The read graph is quite a shock: instead of a smooth line that quickly rises up and then flattens out, the speed and size of the requested data block are almost directly proportional. And the speed is very low. We’d see the same graph in a random read test, but we’re reading from the cache here! Obviously, the HDD does not cache read requests at all. It is only on certain data block sizes that we see its speed jump up to an acceptable level.
Writing is better, yet far from perfect, either. We just can’t explain those wild fluctuations of speed.
Seagate Barracuda LP: work with the buffer
Seagate Barracuda XT, ICH7: work with the buffer
The Seagate Barracuda XT works with the buffer differently than its predecessor. We cannot say that it works better, though. The speed of writing large data blocks is much lower than the speed of reading them, and there are some problems with writing small data blocks. The resulting graph is rugged, with slowdowns on certain data block sizes. The speed of reading large blocks from the buffer has improved, but is not consistent, either.
Seagate Barracuda XT, Marvell 9123: work with the buffer
And here is the loudly touted SATA 600. There is indeed a performance gain as the speed of reading has grown up to 300MBps. Perhaps that’s not much, but anyway. We don’t know if the speed is limited by the Marvell 9123 or the drive’s controller but we are sure that the mainboard’s controller has a very special approach to writing requests into the HDD’s cache: the speed of writing is lower than on the ICH7. Thus, the first implementation of the new SATA version is not blameless.
We carried out one more experiment. We took an ASUS P5WDG2 WS Pro mainboard and installed an add-on card with a Marvell 9123 controller into a PCIe x1 slot. An important notice: this mainboard has PCIe version 1.0 rather than 2.0 as in newer chipsets. Then we measured the speed of working with the disk buffer again.
The results are most illustrative: the PCIe bandwidth proves to be too low and the speed of reading from the buffer plummets to 200MBps. Both graphs go lower than the graphs recorded on the ICH7. It means the new high-speed SATA interface does not enjoy universal support as yet, and you should count in all the factors.
Later on, when this review was nearly complete, we got another add-on card with support for SATA 600 and USB 3.0. It differs from the above-described one in using four PCI Express lanes. We will leave USB 3.0 for an upcoming report and will focus on the Seagate Barracuda XT here.
Well, the PCI Express bus is wide enough here to allow for a speed of 350MBps when reading from the HDD’s cache. This is even better than with the mainboard-integrated controller, which must be limited by its bus, too. The speed of writing into the buffer remains low, though. This must be a peculiarity of the current version of the Marvell 9123 driver.
Western Digital Caviar Green: work with the buffer
Western Digital Caviar Black: work with the buffer
Western Digital RE4: work with the buffer
Compared with the previous drives’ results, Western Digital’s products deliver highly consistent performance. And we must note that their results are better than those of their opponents.
After the graphs, the comparative diagram does not have much to say. You can only learn that the SATA 600 interface in the Marvell 9123 implementation indeed improves the speed of reading from the buffer but worsens the speed of writing into it. Otherwise, the HDDs are all alike. The lack of details in the diagram negates the existing differences between the tested products.
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 will be discussing graphs and diagrams.
We can’t expect any surprises in this group of tests. We already know the drives’ top speeds from the low-level read test and writing is usually the same as reading. Still, we should take a look at how the drives process small data blocks. Western Digital’s products improve noticeably, the newer models probably having a faster processor than what the power-efficient Caviar Green has. Interestingly, the RE4 coincides with the Caviar Black at reading but is somewhat slower at writing small blocks of data. We cannot really find a reason for that.
The Hitachi Deskstar 7K2000 is quite a miserable view compared with the others. It either has a very weak processor or poor firmware. Whatever the reason, this drive’s performance with small data blocks is very low. Take note that it achieves its top speed on 64KB blocks only whereas the others do the same on 8KB blocks.
For 10 minutes IOMeter is sending a stream of requests to read and write 512-byte data blocks with a request queue of 1. The total of requests processed by each HDD is much larger than its cache, so we get a sustained response time that doesn’t depend on the HDD’s buffer size.
This review abounds in surprises! We had hoped that Western Digital’s drives would deliver a good response time at reading but we had not expected such excellent results. The response time of lower than 12 milliseconds is superb for 7200rpm products! Frankly speaking, we don’t even remember easily when we saw such a low response time before. And you should keep it in mind that these HDDs have full-size 500GB platters with over 200,000 tracks each. We want to applaud to Western Digital for such a clever implementation of a composite heads actuator.
Seagate Barracuda XT doesn’t look brilliant in comparison with Western Digital’s as well as other drives. It can only surpass the Caviar Green whereas the Barracuda LP with its 5900rpm has better results. It is unclear for us why the Barracuda XT, having a lower seek latency, delivers a higher response time. Interestingly, the drive shows identical results on both controllers. This again proves the fact that the statistical method of this test helps minimize the influence of secondary factors.
There are no surprises when it comes to writing. We can note the highly effective deferred writing of the Hitachi and the improved deferred writing algorithms in Seagate’s products (the XT is much better than the LP).
Next goes the test of average positioning speed. The drive is being bombarded with read requests like in the response time test, and we calculate the difference between the LBA addresses of the previous and next requests and divide it by the time it took to perform the request. In other words, we have the distance (in gigabytes) the drive can run through in 1 second.
High recording density and fast heads are the two key factors of success in this test. Western Digital’s HDDs have both and easily take two top places. The Seagate XT, probably due to its high response time, gives way to the two power-efficient models. The Hitachi is poor as its recording density is lower than that of the other HDDs. Even its 5-platter design (the number of platters is a certain advantage in this test) can’t save the day.
Now we will see the dependence between the drives’ performance in random read and write modes on the size of the data block.
We will discuss the results in two ways. 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.
Extraordinary things put aside, the results of this group of tests can be predicted from the previously gathered data: the response time is the crucial factor for small data blocks, and the sequential speed is for large data blocks. This is what we see here except that the Seagate Barracuda XT falls behind the 7200rpm WD drives when writing large data blocks on both controllers. The Hitachi 7K2000 looks very good for a HDD with lower-density platters.
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 this link to view the tabled results for the IOMeter: Database pattern.
We will build diagrams for request queue depths of 1, 16 and 256.
Western Digital’s new HDDs are beyond competition at the shortest queue depth. They can only be challenged by the Hitachi 7K2000 in terms of deferred writing efficiency, yet the latter’s high response time prevents it from offering any serious competition. The new Seagate does not impress at all, competing only with the WD Caviar Green and falling behind the Barracuda LP at reading.
When the queue grows longer, WD’s pair goes ahead, boasting highly effective request reordering algorithms. The Hitachi is the only more or less worthy opponent. The Seagate Barracuda XT is mediocre and its slower cousin Barracuda LP shows no deferred writing at all.
Take note that there is a performance slump on the Marvell 9123 controller at a certain load. Hopefully, this is just a single problem.
Western Digital’s drives are still very good at the maximum queue depth but their performance is lowering as the share of writes increases. It looks like the HDDs allot all their resources to read requests, nearly ignoring write requests altogether. It is only when there are no reads in the queue left that they wake up and enable their highly effective deferred writing algorithms. Whatever the reason, they fall behind the Hitachi at high percentages of writes due to this behavior.
The Seagate XT still cannot get any of our praise. On one hand, it is more effective than the Hitachi at reading (but far from matching the performance of WD’s products). But on the other hand, its deferred writing is not very effective. All of this refers to the ICH7 controller. When connected to the Marvell 9123, the HDD is as poor as 5400rpm models.
Winding up this part of our tests, we will build diagrams showing each drive’s performance at five different queue depths.
The Hitachi has everything – deferred writing, request reordering and all – but it might be more effective at reordering requests at long queue depths.
The Seagate Barracuda LP shows very modest, nearly absent, deferred writing and its results at queue depths of 16 and 4 requests only differ in the case of pure random reading. Interestingly, this HDD behaved differently in the last test on the Promise controller. Its performance was better at writing, for example. This is a vivid example of the effect that the disk controller’s driver can make.
The Barracuda XT is influenced by the controller, too. When connected to the ICH7, this is a nice HDD with neat request reordering algorithms and modest deferred writing. Its high response time spoils its performance the most.
The Marvell controller adds a few unpleasant touches into this picture. First, it does not want to increase performance at long queue depths, which is a controller’s fault indeed. Second, we see sudden performance slumps in each graphs which must be the result of some conflicts between the controller’s and the HDD’s algorithms.
The graphs of Western Digital’s Caviar Black and RE4 resemble the Caviar Green’s but go higher and are stretched out vertically. So, we guess that Western Digital is still using its unified and highly effective firmware. The new products boast impressive NCQ algorithms which seem to conflict with deferred writing at long queue depths. For example, at a queue depth of 16 requests we can already see a performance hit at 90% writes. Interestingly, the Caviar Green holds on longer although it has a smaller cache.
The disk controller’s influence on performance can be observed again. On the Promise controller the Caviar Green had no performance hits at 80-90% writes (we use one and the same disk with the same firmware). It is because of such variations that we use the same testbed and methods to test all hard disk drives in our labs.
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.
Under the reads-only load Western Digital’s 7200rpm drives have no rivals. Their opponents are downright poor and hardly any better than the Barracuda LP. It is clear that the Marvell 9123 cannot work with queue depths longer than 32 requests – the graph becomes a horizontal straight line then.
Western Digital’s position does not change when there appear write requests in the load. The Barracuda XT falls behind the Hitachi as the latter has more effective deferred writing. We can recall the problems the Barracuda LP had in IOMeter: Database at short queue depths. Here, they result in the graph becoming flat while the other HDDs’ performance is increasing along with the queue depth (which is important as well-balanced disk subsystems usually work within this range of loads).
The Barracuda LP looks bad for the same reasons when it comes to typical workstation loads. The Barracuda XT on the Marvell 9123 slows down after a queue depth of 16 requests. Well, even on the ICH7 controller this HDD cannot catch up with the Hitachi 7K2000 and is better than the WD Caviar Green at short queue depths only.
When the test zone is limited to 32 gigabytes, HDDs with faster heads lose their advantage. As a result, the Seagate Barracuda XT wins at short queue depths while the Hitachi is similar to the WD Caviar Green in performance. The RE4 is for the first time faster than the Caviar Black. The Barracuda XT on the Marvell 9123 controller suffers a performance hit at queue depths longer than 16 requests.
The multithreaded tests simulate a situation when there are one to four clients accessing the hard disk at the same time – the clients’ address zones do not overlap. We will 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:
It’s simple with multithreaded reading: Seagate’s HDDs suffer the most from the addition of new data threads. Western Digital’s HDDs cope somewhat better and the Hitachi 7K2000 is the winner with the lowest performance hit at multiple threads.
The newcomers are all good at multithreaded writing, but the Seagate Barracuda XT on the ICH7 has a sudden performance hit at two data threads but then improves. The Hitachi 7K2000 is slower than the others at three and four threads, though. This may be due to its smaller cache.
For this test two 32GB partitions are created on the drive and formatted in NTFS and then in FAT32. A file-set is then created, read from the drive, copied within the same partition and copied into another partition. The time taken to perform these operations is measured and the speed of the drive 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 drive is working with two threads (one for reading and one for writing) when copying files.
You should be aware that the copying test not only indicates the speed of copying within the same HDD but is also indicative of the latter’s behavior under complex load. In fact, the HDD is processing two data threads then, one for reading and another for writing.
This test produces too much data, so we will only discuss the results achieved in NTFS in the Install, ISO and Programs file-sets. You can use the link below to view full results:
Western Digital’s drives are ahead when writing files irrespective of the specific file-set. The Hitachi is good with large ISO files but falls behind its opponents when processing the small files of the Programs pattern, although Hitachi’s older HDDs used to behave in the opposite manner. We wonder if this is due to our transition to the ICH7 controller or to a dramatic overhaul of Hitachi’s firmware.
When reading large files, the HDDs are ranked according to their results in the IOMeter: Sequential Read test with one exception: the Seagate Barracuda XT on the Marvell 9123 falls behind its counterpart on the ICH7 controller for some reason. The same gap, even though smaller, can be seen with the other file-sets.
Copying is very similar to writing: Western Digital’s drives are ahead (you can easily see how superior their firmware is as even the Caviar Green competes successfully with the HDDs from other makers) and the Hitachi 7K2000 is very fast on large files, without showing anything exceptional on small files.
PCMark 2005 has the same tests as the 2004 version (not only in names, but also in results as we have seen a lot of times), so we only discuss one test from PCMark 2004 which is not available in the 2005 version. It is called File Copying and measures the speed of copying some set of files. The other results can be learned from the table. The PCMark 2005 tests are:
The final result is the mean average of ten runs of each test. You can view the detailed tabled results here.
PCMark does not tell us anything new. Like in FC-Test, Western Digital's new products are beyond competition.
These three tests all fit into the same picture: Western Digital’s drives and the Barracuda XT are in the lead. The latter drive is only really fast on the ICH7 controller. For all its SATA 600 support, the Marvell 9123 looks bad. It even lowers the drive’s performance.
The same goes for the Virus Scan test which is highly sensitive to caching mechanisms. The power-efficient WD Caviar Green is poor in this test, losing not only to the models with 64MB cache but also to those that, like itself, have 32MB of cache memory.
The standings of this benchmark are different from what we have seen in FC-Test. Here, the HDDs are ranked according to their sequential speeds, but the Seagate Barracuda XT is somewhat better on the ICH7. If connected to the Marvell 9123 controller, that drive is somewhat slower than its 7200rpm opponents. The Hitachi 7K2000 does not betray that its recording density is lower than that of the other HDDs.
We see the same trio of leaders and are once again reminded of the fact that not all controllers are good in practical terms even if theoretically they are supposed to be faster.
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.
There are a lot of subtests here but the standings do not change much. The resulting scores correctly reflect the HDDs’ highs and lows. Western Digital’s 7200rpm products are ahead, the server-oriented RE4 being somewhat faster than its desktop counterpart under some loads. Third place goes to the Seagate Barracuda XT which is again faster on the ICH7 than on the Marvell 9123. The Hitachi 7K2000 fits in between the rest of the newer products and the models with lower spindle speed: its lower recording density shows up after all.
Next goes our homemade test of defragmentation speed. We created a very defragmented file system on a 32GB partition of a 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 disk we want to test. 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. We run this test with AHCI enabled. For more information about it, you can refer to this article.
The numbers are interesting enough. Western Digital’s HDDs take top places again, boasting very good results of less than 18 minutes. The Hitachi 7K2000 makes it to third place, obviously benefiting by its 5-platter design and good response time in this test. The Seagate Barracuda XT looks very good, especially in comparison with its predecessor. While the LP is just as bad as Seagate’s older products (which used to be sluggish at defragmentation), the XT is almost competitive to its opponents.
Now we are going to show you one more interesting test in which we use WinRAR version 3.8 to compress and then uncompress a 1.13GB folder with 8118 files in 671 subfolders. The files are documents and images in various formats. These operations are done on the tested drive. This test depends heavily on CPU performance, but the storage device affects its speed, too.
The Seagate Barracuda XT is tested only on the ICH7 here. The platform with the Marvell 9123 has such a powerful processor that the HDD’s influence cannot be observed.
We’ve got an interesting picture when creating the archive: The Western Digital RE4 is an indisputable leader, differing dramatically from its Caviar Black cousin. The rest of the HDDs go neck and neck, the models with lower spindle rotation speed being a tiny bit better. That’s a curious outcome.
The HDDs differ more when unpacking the archive because the CPU’s influence is lower. Western Digital’s drives are ahead again, even the Caviar Green outperforming its opponents.
You can refer to our article called Hard Disk Drive Power Consumption Measurements: X-bit’s Methodology in Depth for details on this test. We will just list the specific modes we measure the power consumption in:
Let’s check out each mode one by one.
Seagate’s HDDs need the highest start-up current (over 2A on the 12V alone) irrespective of the speed the drive’s platters are going to rotate at. They have the lowest 5V consumption, but every other HDD is quite modest in this respect, too. None of them needs more than 1 ampere from this power rail. Western Digital’s products are the most economical overall.
When there is no load, the Hitachi looks poor compared to the others. It has one platter more than its opponents, yet even its power draw fits into 8 watts. Western Digital’s products are just perfect, their electronics consuming only half the power their predecessors needed. The Barracuda XT’s electronics consumes quite a lot, which must be a tradeoff for SATA 600.
The Western Digital drives’ electronics is somewhat hungrier in comparison with the other HDDs at random reading, but the 12V line is more important here. The Seagate Barracuda XT, having suffered from its slow heads throughout this entire test session, shows its best now. Its overall power consumption is similar to the HDDs with lower spindle rotation speed. An inexplicable fact can be observed with Western Digital’s HDDs: the RE4, being somewhat faster through our tests, proves to need less power than the Caviar Black. The Hitachi 7K2000 is poor: besides five platters, it has to move a block of ten rather than eight (as in the other HDDs) heads. Of course, it is more economical than the previous 5-platter product (which had a power consumption of 16 watts) but not as good as its opponents.
We see a similar picture at random writing: the Seagate XT is competing with the power-efficient HDDs among which the Barracuda LP, thanks to its economical electronics, outperforms the WD Caviar Green, which needs less power from the 12V line. Yes, Western Digital’s HDDs need more power for their electronics with high-performance firmware than the 1-terabyte RE3 and Caviar Black models. Perhaps this is the contribution of the additional piezoelectric heads actuator. Anyway, the Hitachi 7K2000 still remains the most voracious drive as its mechanics consumes too much.
The standings are almost the same at sequential reading and writing: the power-efficient WD Caviar Green and Seagate Barracuda LP are more economical than the 7200rpm products. Among the latter, the Seagate and Hitachi are competing for top place whereas Western Digital’s HDDs still need a lot of power for their high-performance electronics. Interestingly, the RE4 needs less power from the 12V line than the Caviar Black.
What does this test session sum up to? First off, the Hitachi is a highly specific product. It is oriented at server (more specifically, multithreaded) loads and is utterly hopeless under loads typical of desktop PCs. The 5-platter design does not help Hitachi now. Its HDD is inferior to the higher-density drives from WD and Seagate and is also very hot. The single argument in favor of this product is its lower price.
It is simple with the Seagate drive: the high access time cannot be compensated by the 64MB buffer and faster interface. The Barracuda XT is inferior to WD’s models through most of the tests but consumes less power.
Western Digital’s HDDs get all of our praise. They are excellent in server tests, win PCMark, perform nicely under multithreaded loads, and rout their opponents in the defragmentation and WinRAR tests.
Therefore, summing up the results of our today's test session we are proud to award 2 TB Western Digital RE4 hard disk drive with our Editor's Choice title:
In its turn, 2 TB Western Digital Caviar Black receives our Recommended Buy title:
Thus, if you want a fast 2-terabyte hard disk drive, we recommend you Western Digital in the first place.