Date: April 22, 2013
Author(s): Robert Tanner
Have you ever had a craving for a hard drive the same size as those Girl Scout Thin Mint cookies? Seagate has just the drive for you, and anyone else who’s in the market for a svelte 7mm laptop drive but needs performance at an affordable price. Seagate’s Solid-State Hybrid Thin drive may be small, but it may just be the drive you’re looking for.
SSDs are a hot market right now; they offer the most direct, tangible boost to overall performance and system responsiveness on a level that hasn’t been seen since the migration away from single-core processors. If you have used a system that had the OS & programs installed on an SSD, then you know. Even if not, it probably isn’t too hard to imagine what using a smartphone or tablet would feel like if it had a mechanical disk drive whirring inside instead of flash memory.
The secret to an SSD’s success starts with the lower access latency that NAND flash offers compared to magnetic drives. They aren’t just a single order-of-magnitude lower, but actually a whopping 2-3 times faster (14ms vs 0.1ms, typically) when seeking data. It’s one of the reasons smartphones and tablets ship exclusively with the same sort of NAND flash memory, even if the average laptop or desktop doesn’t. Laptops and PCs need significantly more storage capacity than a tablet or smartphone, so a comparable amount of NAND in them still raises the overall cost of a computer beyond the point where it would be uncompetitive versus others in the industry.
Seagate is not just looking to change that but is doing something about it. It started with the launch of the Momentus XT family, a hybrid drive that paired a mechanical drive with SLC flash NAND. The only drawback was that the XT still commanded an unfortunately high premium over regular mechanical drives. That’s where Seagate’s new “SSHD” comes in.
Seagate’s Solid-State Hybrid Drive family is the 3rd generation of hybrid drives, and what differentiates it over past models is the use of MLC NAND, and price. Sporting an MSRP ranging from $0.08-0.15 cents per gigabyte (or was that Gibibyte?) it is priced competitively with other mechanical drives while still promising to offer “SSD like” levels of performance. For comparison, as of this writing even the best priced SSD still slots in at $0.60 cents per GB/GiB, with lower capacity models running closer to $0.80.
|Seagate SSHD Family|
|Seagate Laptop SSHD||500GB||2.5″||7mm||1||5400 RPM||8GB MLC||$79|
|Seagate Laptop SSHD||1TB||2.5″||9.5mm||2||5400 RPM||8GB MLC||$99|
|Seagate Desktop SSHD||1TB||3.5″||???||1||7200 RPM||8GB MLC||$99|
|Seagate Desktop SSHD||2TB||3.5″||???||2||7200 RPM||8GB MLC||$149|
The SSHD name is the new designation for Seagate’s hybrid drives and makes it easy to distinguish it from previous generation XT models. On average, Hybrid models will feature a greater areal density (fewer platters) compared to the XT generation which will improve performance; on the flipside, all 2.5” laptop models are limited to just 5400RPM. All models include a fixed 8GB of MLC NAND which will operate as cache for both reads and writes for most frequently accessed data. Unlike typical caching solutions, the entire caching process takes place at the drive level, meaning no software, no special drivers, and no special OS consideration is needed with an SSHD. Users can treat it as a normal hard disk drive in all respects (even including defragmentation tools) which makes the Seagate’s Solid-State Hybrid Drive family as easy to use as any other hard drive.
Seagate sent us a pair of the most exciting model in the SSHD family, the “Seagate Solid-State Hybrid Laptop Thin” which is an astonishingly tiny 500GB, 7mm tall laptop hybrid drive with 8GB of MLC NAND. These “Thin” model drives will be especially important for laptop users, most of which only have space for only a single drive and don’t have physical space for both an SSD for performance and an HDD for capacity to the laptop.
Before jumping into our results, we need to first explain how we conducted our testing. Our readers know that when benchmarking SSDs we normally run all tests five times, drop the highest and lowest results and average the middle three for our final result. That testing methodology isn’t exactly fair nor exactly accurate when it comes to hybrid drives like the SSHD. So in our graphs we have decided to include the best, worst, and our standard result from all five runs.
We included a representative, budget model SSD and a 7200RPM desktop drive as the best comparison points to showcase where the SSHD performs in relation to a typical HDD and SSD. Additionally, although desktop SSHDs are more applicable for and would give much better performance due to their higher rotation speed, we went ahead and added results for both Laptop Thin drives in a RAID 0 setup just for the heck of it!
At Techgage, we strive to make sure our results are as accurate and real-world applicable as possible. We list most of the steps and processes involved in setting up and conducting our benchmarking process below, but in the interests of brevity we can’t mention every last detail. If there is any pertinent information that we’ve inadvertently omitted or you have any thoughts, suggestions, or critiques, then please feel free to email us or post directly in our forums. This site exists for readers like you and we value your input.
The table below lists the hardware used in our current storage-testing machine, which remains unchanged throughout all of our testing, with the obvious exception of the storage device. Each drive used for the sake of comparison is also listed here.
|Techgage Solid-State Drive Test System|
|Processor||Intel Core i7-2600 – 3.80GHz (Locked) Quad-Core|
|Motherboard||ASUS P8P67 Deluxe|
|Memory||4GB Kingston DDR3-2133|
|Graphics||AMD Radeon HD 5770|
|Storage||Hitachi 7200RPM 2TB
Kingston V300 120GB SSD
Seagate Laptop Thin SSHD 500GB
|Power Supply||Antec NeoHE 550W|
|Et cetera||Dell 2407WFP (1920×1200)
Windows 7 Ultimate SP1 64-bit
Our Windows 7 Desktop for SSD Testing
When preparing our SSD testbed for benchmarking we follow these guidelines:
Windows 7 Optimizations
For our new Sandy Bridge storage testbed we have migrated to using test images for our drives. All drives are imaged with the cloned test image to ensure all drivers, programs, and settings remain identical for testing purposes. We feel disk cloning software and SSD controller technology has matured to the point where potential issues such as non-aligned sectors are no longer a potential issue.
For testing, we run all tests five times dropping the highest and lowest results, then take the average of the middle three. And who said that college statistics class wouldn’t prove useful? If any anomalous results are seen the test will be run again. Given the complexities of modern computers, and especially today’s operating systems and the software that runs on them, we feel this provides the most accurate results possible.
Finally, we are seeking to constantly improve and expand upon our SSD testing methodology. We are always actively seeking real-world workload scenarios that are bottlenecked by hard drives, so if you have any suggestions whatsoever or there is a program you would like to see included in our SSD content, then please drop by our forums and let us know! We are always looking to expand our SSD benchmarks and provide more useful and real-world results, and not just synthetic numbers.
Futuremark’s PCMark benchmarking suite should need no introduction; it has been a staple of PC benchmarks for the better half of a decade. It includes over 25 individual workloads designed to measure all aspects of system performance and gives individual scores in each test as well as an overall system performance score for easy system comparisons.
PCMark 7 offers a more accurate measure of performance as compared to its predecessor, PCMark Vantage. The storage scoring metrics especially were significantly re-tuned and optimized with SSDs in mind to give a more balanced disk subsystem score.
If you missed it and are wondering how to interpret our graphs, check back to the last two paragraphs on the first page! Now jumping into our results, the SSHD Thin shows some fairly consistent results in the PCMark tests, although the “best” results give a considerable improvement in the gaming and application load subtests. When the right data is in the 8GB cache the SSHD Thin can post a best time that is faster than its average result in RAID 0.
The overall PCMark Suite score gives us some telling results. Despite its slower rotational speed and tiny 7mm single-platter design, the “Laptop Thin” not only surpasses the desktop hard drive, but delivers an average result closer to the SSD than the HDD. Obviously, as we delve deeper into the actual storage tests the SSD begins to pull away from the SSHD, but we can clearly see that the claim of near SSD-like performance has merit.
Between a 7200RPM mechanical drive and a 5400RPM SSHD Thin, it’s clear which one people would prefer to have. The SSHD Thin result easily outperforms the HDD result in every single test and by a considerable amount in the Application Load and Gaming subtests in particular. I guess rotational speed isn’t everything!
Originally developed by Intel – and since given to the open-source community – Iometer (pronounced “eyeawmeter”, like thermometer) is one of the best storage-testing applications available, for a couple of reasons. The first, and primary, is that it’s completely customizable, and if you have a specific workload you need to test a drive with, you can easily accomplish it here.
Secondly, it bypasses the Windows disk subsystem entirely, meaning it bypasses the OS drivers and writes directly to the storage media. This has important implications, such as it means Windows 7 cannot correctly align Iometer to match the SSD or HDD sector alignment.
We have updated our test suite to the latest stable 1.10 rc1 build of Iometer, which was released in December, 2010. This version makes some changes to be aware of; specifically, it gives the option for three types of data sets used during testing. 2006 and earlier versions used a pseudo-random dataset for testing, while the 1.10 build will default to a “repeating bytes” test pattern. A full random test mode was also added. To avoid giving SandForce drives an unfair advantage (they rely on data compression to achieve their performance), we will stick to the pseudo-random test pattern for all of our testing.
We have configured Iometer for correct 4KB disk alignment using a single 8GB test file from within Windows, meaning they are acting as the host OS drive with no other drives in the system. We run individual random 4KB read and write tests at a queue depth of 3 and again at 32. Then we run the 128KB sequential read & write tests using a queue depth of 1. In addition, all drives are in a dirty state prior to testing – this means results will not be comparable to advertised manufacturer results. Our goal is to measure end-user performance under real-world conditions, and so our testing reflects typical SSD performance after it has been used for some length of time in a system. Each test pattern is run for 5 minutes to achieve an average result.
In addition, we have created three Iometer disk usage scenarios that should roughly approximate database, file server, and workstation usage patterns. These scenarios are run individually for 10 minutes each within an 8GB file on the drive, which is an unusually harsh scenario for any sort of SSD. Drives that are able to offer better sustained performance over time and those that favor certain file size accesses will do well here. All three tests are configured for a queue depth of 32 to show which drives are best capable of dealing with heavy workload scenarios.
“IOPS” is simply the measure of performance relative to a certain disk access size, specifically 4KB or 512 bytes, or any size desired. Typically with SSDs when speaking about IOPS it is referred to on the assumption of 4KB accesses. With this in mind, it is easy to convert between IOPS and MB/s. Iometer provides both types of results to us and for the sake of concise graphs, brevity, and easily understandable results, we have elected to use MB/s for the 4KB and 128KB tests. For reference: IOPS = (MBps Throughput / KB per IO) * 1024 and MBps = (IOPS * KB per IO) / 1024.
We run Iometer once; five minutes for the file access tests and ten minutes for the three suite tests The program averages the results. We won’t have Best or Worst times for this test, not that it really matters as Iometer is a program designed for massive server disk arrays and SANs, not single mechanical disk drives.
Despite this, the SSHD manages to give marginally better random read 4KB results than our desktop drive and nearly matches it in sequential performance. The random write 4KB results are actually 4 times better than the desktop drive as well which is surprising.
The three Iometer suite tests are not intended for mechanical drives and would normally be seen for large RAID arrays or SANs.
As the name implies, AS SSD is a nifty little program written exclusively for solid-state drives. It can still be run on a mechanical hard drive just for fun, but be warned: what takes a few minutes on an SSD will require the better part of an hour on an HDD! It is freely available for download here.
This handy tool measures sequential reads and writes in addition to the important 4KB random reads and writes, then ranks the results with a final score for quick comparison with other SSDs. In addition to the main test there is a secondary benchmark that simulates the type of data transferred for ISO, Program, and Game files. We selected this program for its precision, ability to generate large file sizes on-the-fly, and because it is written to bypass Windows 7’s automatic caching system.
AS SSD is another test not designed for mechanical drives, and when we say that, we mean it. A single AS SSD run would take seconds on an SSD, but required two full hours on the SSHD due to how the testing is conducted. As such we only did two runs and reported the best result. Curiously, the RAID 0 setup fared even worse in the sequential read test, although we did three runs just to be sure.
The SSHD isn’t able to cache anything in the Copy tests, and delivers results behind those of the 2TB drive. Overall scores are nearly identical between them, however.
HD Tune is still primarily an HDD benchmark, but we include it as an alternative for those consumers that prefer it for one reason or another. The free version does not perform write tests, but otherwise is available for free here.
HD Tune, thankfully, is a tool designed for HDDs, but Seagate warns that it isn’t suited as an accurate representation of performance due to the caching mechanism that SSHDs use. As such it should be no surprise to see results once again mirroring the other mechanical drive, although the SSHD does deliver better random read performance.
Finally, we reach the first of our real-world tests where there are no unusual testing or scoring algorithms to leave us scratching our heads, just simple tests to see how an SSD changes actual system performance.
For the File Transfer test we took a 4.5GB compressed archive and measured how much time was required to transfer the file to another folder on the same drive. Keep in mind that with a hard disk, this requires the actuator arm to seek back and forth between the source and destination sectors on the disk platter, with the destination sectors often not sequentially aligned. In contrast, any SSD can concurrently perform read and write operations simultaneously on any NAND chip without regard to spatial considerations of bits strewn randomly around a disk platter, which gives them a large advantage here.
Moving into our real-world tests we can see that the lower rotational speed does adversely affect large sequential file transfers, which is an unfortunate tradeoff of having an ultrathin 7mm form factor. Interestingly we see the SSHD is caching at least some of the data as after a few runs it shaves 37 seconds off its average time.
Desktop SSHD models will likely exceed our 2TB drive’s performance thanks to having a matching rotational speed combined with a much higher areal platter density.
Either you’ve heard of FLAC, or it is an integral part of your digital life. But iTunes and Apple devices do not support FLAC files, leaving those with discerning ears forced to use Apple’s Lossless codec. dBpoweramp makes it possible to convert between them utilizing as many threads as are available to the system.
In this test, we take 10 albums amounting to 4GB of FLAC files and convert them to Apple’s lossless format. This creates exactly 3.96GB of new data. This scenario is even more applicable for those users with six or more physical CPU cores available, because as the core count increases, the more the storage system will become the actual bottleneck. Our test rig is limited to only a quad-core processor, but even then we can see clear differences amongst the various contenders.
The constant switching between reads and writes in this test does not favor mechanical drives at all because the actuator arm is constantly having to swing across the platter surface. As we might expect, the large, sequential workload isn’t suited for caching although the SSHD does manage to significantly increase performance over the worst result, and even shaves two minutes off its average time with its best result.
Real-world results are surprisingly hard to come by when testing SSDs. It is extremely easy to showcase just how much faster any SSD on the market is compared to even a modern mechanical disk drive. However, when we try to compare SSD to SSD, differences can amount to just a few seconds or even a fraction of a second, often well inside the margin of error (and human reflexes), making any results obtained meaningless.
We are always eager to hear about any demanding storage workloads our readers may have, but in an effort to get around this problem, we have put together three batch test files that target three levels of intensity.
Firstly we have our light batch file, which we drop into the Windows Startup folder. Windows 7 will execute and load various programs and commands as it boots, making it perhaps the most easily pertinent of our three tests. Almost everyone has an array of programs that starts with their OS, ranging from background applications like anti-virus to programs like a browser or music player.
This batch file will load four websites in Firefox, start Photoshop CS5 and load five 5MB or greater images, and load 15MB of data in Word, Excel, and Powerpoint documents. Several background utilities will also load; a PDF file and compressed file are opened for viewing, and of course, since nobody likes to work without listening to some music, we have our favorite 56MB FLAC file playing the entire time. Obviously, all of this takes place while Windows 7 itself is still loading. We start timing from the moment the machine is powered on to the moment the last program finishes loading – and it isn’t as long as you might think. (We provide raw cold boot times on the next page for direct comparison).
Our medium batch test is similar although we apply the use of timers to space apart the commands. Instead of booting, time begins from the moment we execute the batch file until the moment all tasks have completed. The medium test also consists of the following:
To keep things simple, the heavy batch test is identical to the medium test in all respects, save for one important addition. Computer users coming from HDDs will be familiar with the slowdown or even molasses-like feeling that occurs from having an anti-virus or anti-malware scan running in the background. SSDs scoff at this sort of thing however, and the typical SSD user wouldn’t think twice about running an anti-virus scan at the same time as playing a fullscreen game since framerates will remain relatively unaffected.
The heavy test will capitalize on this by running an anti-virus scan from Microsoft Security Essentials on a static, unchanging 5.1GB test folder that contains 19,748 files and 2,414 sub-folders copied from the Program Files directory. Also worth noting is that because the medium and heavy batch tests are identical save for the AV scan, results between them are directly comparable.
Our batch results are well-suited for caching drives and give some telling results. Firstly, the SSHD Thin is able to deliver fast boot times while loading a couple applications nearly as fast as our sample SSD. Seagate’s SSHD Laptop Thin literally is able to boot and load programs in less than a third of the time of the mechanical drive after it has initially had time to cache the data.
Moving onto our medium test we see the hybrid drive shave a minute and a half once it caches some data, although its best time shaves another full minute off its average result and gives it a 15 second lead over the 2TB drive.
Although the medium results are still good and show that the SSHD will deliver performance far better than a typical 5400RPM laptop hard drive, the limitations of an 8GB cache are coming into play here. Almost 5GB is being written to the disk and more than 1GB in file reads will take place. With 8GB of space to work with, data has to be evicted from cache if new data is being more actively utilized which will lead to some programs bumping others out of that limited 8GB. The best result shows that given enough runs the drive will continue to optimize itself, but for extreme users it is a problem. The heavy batch test again brings the lower rotational speed into play as the anti-virus scan seeks slow down the overall performance.
For the boot test, we perform a cold boot with the stopwatch starting the moment the power button is pressed until the last systray icon has finished loading. A large number of factors can change how fast a computer starts; whether the motherboard uses a BIOS or the newer UEFI; if a RAID controller has to be initialized; to delay timers or other motherboard optimizations. In other words, individual results will vary depending on the system hardware.
For boot times Seagate’s SSHD really shines. Worst case it is still faster than the hard drive, and on average it boots the system to desktop 44% faster. The best time has it delivering boot times that are in SSD territory. Once again we see that caching paying off, and further proof of that “SSD-like” performance claim.
SSDs deliver some of the most benefits to games. Not only can the game load significantly faster so users can hurry up and wait to get through various advertisement screens, but they also boost level or map load times. For games where player immersion into the new world is important, the difference between 15 and 25 seconds can seem huge when waiting for the next part of the level or world to load.
For our new regimen we chose Portal 2 and Civilization V. Portal 2 is already a very well optimized game, but it’s immersive, so we time how long it takes to load the sp_a2.bts6 custscene. With Civilization V‘s recent overhaul to game storage files to help decrease load times, and the new option to disable the intro movie trailer, it becomes possible to time how long it takes to start the game.
On average the SSHD fairs a little worse than the 7200RPM drive, but ends up being 3-5 seconds faster with its best time. Although the worst time in Portal 2 still ties the HDD, there was one run in Civ that faired considerably worse.
Unlike previous hybrids, Seagate states that the SSHD can cache both reads and writes, although the company notes that its algorithm will favor random accesses over sequential ones. Judging by our results, cache eviction was still a problem for the Hybrid drive. That said, it isn’t unexpected given our benchmark suite will read and write significantly more than 8GB of data just per single run. For everyday use, 8GB of cache should just be big enough for the average consumer or daily office job.
The facts are: the standard user doesn’t actually load new data as often as they constantly reload the same programs and same data files, especially where browsers, email clients, and office productivity programs are concerned. Basically, the more often the same programs get used, the larger the benefit those programs will receive. A heavy power user will probably experience cache eviction problems too frequently with 8GB of cache, but they would have also likely migrated to an SSD in any case.
Admittedly, I was initially a strong skeptic when I first heard about Seagate’s new SSHD launch. The past issues regarding the XT prices meant that there seemed to be no place for it in desktops, users could buy an SSD for the asking price and just get a storage drive later. Another problem was that 4GB of cache was simply insufficient for any reliability in caching performance, and even for laptops the premium was hard to justify.
Then as the launch drew near and I saw the launch day prices for the SSHD family, I began to realize I was approaching the subject from the completely wrong angle. Instead of seeing how much less performance an SSHD gives compared to an SSD, think of it as how much additional performance does an SSHD deliver as compared to a mechanical drive. Because when the difference between them is a mere $10-15 dollars, the only focus should be on what they will get you versus a regular mechanical drive.
After it had a few runs to first adjust its caching patterns, the 5400RPM Laptop Thin Hybrid drive was able to tie or outperform our 7200RPM desktop drive in the majority of our tests. Given many laptop drives are still 5400RPM in speed, it may be obvious, but it is worth noting that at this point there is simply no reason to not choose a Hybrid if already buying a 5400RPM drive. Best case, they would likely see their boot times cut literally in half and have their most-often used programs launch tangibly quicker. There are a couple 500GB 7200RPM drives with a svelte 7mm height on the market, but they are few and far between. Even Seagate has already gone on the record stating they would discontinue making 7200RPM laptop drives as they foresee the Hybrids offering a better performance.
As beneficial as SSDs are, they still come with a tremendous price premium over magnetic drives. One can buy a 60GB SSD for the same price as the $79 MSRP of the 500GB Laptop Thin Hybrid, but I suspect very few people could manage to get by with just 60GB of storage on a laptop, or more accurately closer to 40GB with Windows installed. The 7mm height Laptop Thin Hybrid commands about a $15 premium over the cheapest 7mm laptop drive of equal capacity, while doubling the capacity to 1TB only adds another $20 to the price.
Seagate’s Hybrid is an interesting approach, one which that hopefully OEMs will begin incorporating as an option in their systems directly, because in all fairness the Hybrid isn’t a product one should buy unless they are either 1) already in need of a replacement drive, or 2) deciding whether to spring for one as part of a new system. If the consumer is buying to simply replace a working HDD then they would have the ability to, and be best served by saving up a little longer until they can spring for a full 120GB SSD.
For desktops, I am not yet convinced, but for laptops where a single drive is the only viable option then the answer is most definitely “yes”. If already in need of a drive then investing $10-15 more for a hybrid drive seems like a no-brainer when an SSD simply isn’t an option. Performance won’t equal a solid-state drive and large data transfers will take a slight hit as well, but it will be better than even a 7200RPM drive where it counts. Users can expect noticeable improvements in their most often used applications and enjoy significantly improved boot times as well.
Seagate’s SSHD lineup is an intriguing new alternative that attempts to bridge the divide between SSDs and HDDs. It offers the capacity of a traditional drive yet throws in the allure of near-SSD performance for just a marginal increase in cost. If you are in the market for a laptop drive and an SSD is out of the question, then Seagate’s Solid-State Hybrid Thin 500GB is the drive to get. At this point there simply is no reason to choose a regular 5400RPM laptop hard drive at all anymore, as Seagate’s Hybrid Thin 500GB costs a few dollars more but can offer considerable boosts in performance where it counts the most.
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