OCZ Agility 3 240GB SSD Review

[AkG]

Ever since the introduction of 25nm NAND and SandForce’s SF2281 SATA 6Gbps controllers, the market has seen a tidal wave of drives all competing in the same categories. The end result is some companies like OCZ have strategically placed SSDs at every conceivable price point, from the entry level all the way up to ultra expensive flagship drives. The Agility 3 240GB is currently considered the lowest rung on OCZ’s “high performance, high capacity”, ladder but it still retails for a hefty $390 at most retailers.

For many consumers, 120GB of space isn’t enough yet their budget just can’t accommodate an enthusiast grade drive like the Vertex 3 or Vertex 3 MAXIOPS. OCZ has catered to this particular niche by simply including cost effective ONFi 1.0 NAND alongside the ever popular SF2281 controller. Naturally, the use of this less expensive will have a negative effect upon performance when compared to the ONFI 2.x modules used by the flagship drives. But will a consumer really notice the difference in their day to day usage patterns?

​

$500. Throughout this review, remember that number because it represents the going price of the very popular Vertex 3 240GB. It is also the reason why the Agility 3 will likely tickly the fancy of many first time SSD users who are afraid of the capacity limitations of other drives. We also have to remember that the popular Crucial M4 256GB is priced only slightly higher than this model, yet relies on a slightly different design: a Marvel 9174 controller and ONFi 2 NAND. Unfortunately, this could make the Agility 3 a tough sell.

While this drive’s enclosure has been designed with a classic OCZ color scheme, there is one major difference between this and other models we have looked at: it materials. In what looks like an attempt to save a few bucks, only the case’s bottom is metal while the top half is plastic. Luckily we’re talking about an SSD here so the use of plastic isn’t too concerning but let’s hope this isn’t an omen of things to come like it was with the plastic clad AData S592.

​

As expected, the interior architecture is very similar to that of nearly every SandForce SF2281-based drive we have looked at recently. There are 16 NAND populating the PCB’s 16 Integrated Circuit slots and a SandForce 2281 controller.

​

Interestingly, we’re seeing an advent of OCZ branded NAND chips but while the label may say “OCZ” they are actually 25nm ONFi 1 Asynchronous dual die NAND modules made by Micron.

Also noteworthy – and much like the Patriot Pyro 120GB we reviewed recently, the Agility 3 does not come with a 2.5” to 3.5” adapter. Many of OCZ’s competitors have seen fit to include this inexpensive accessory and this potential limitation should be taken into consideration before buying this SSD.

 

[AkG]

Introducing the SandForce SF2000 Family

Introducing the SandForce SF2000 Family

​

As you are probably well aware by now, there are actually many different models which make up the next generation of SandForce controllers. Much like Intel’s socket 1155 i3/i5/i7 series of processors, all these different SandForce numbers represent slightly different tweaks and features, but all are basically built upon the same SF2000 foundation.

In grand total there are eight SF2000 iterations, but for the most part we won't see most of them in the retail channel. Take for example the SF2141; this is a cut down 4 channel, 24bit RS ECC, SATA 3GB/s controller which probably wont see much fan fare outside of truly budget SSDs. The easiest way to think about this one is to consider it the low end of SF2000 drives. Stepping up a level to 8 channels (and 55bit BCH ECC) but still SATA 3GB/s only is the SF2181 which you can consider the mid range of this generation. This one will probably be featured in more mid-tier next generation SSDs as it has better error correction abilities, yet cannot directly compete with the true stars of the SF200 consumer line: the SF 2281.

The only difference between the two “real” consumer grade SF2000 SATA 6G controllers most likely to be seen (the SF2281 and SF2282) is the one -the 2282- is only for extra large 512GB and higher drives (though the SF2281 can handle 512GB of NAND) and is a larger chip. These are the two flagship products as such have received all the features and all the tweaks which are going to become synonymous with the SF2000 consumer class controllers.

The other four controllers are for enterprise environments and boast features such as eMLC compatibility, Military Erase, SAS and super capacitor capabilities.

Features

​

The SF2000 controller series is built upon the same architecture as the original SF1000 series. You get DuraWrite, RAISE and all the other features but these have all undergone enhancements and tweaking.

​

The original SF1000 series had ECC of 24bits per 512byte sector of ECC; whereas the new controller has 55bits. The type of ECC has changed as well. The original used the more simplistic Reed-Solomon (aka “RS”) ECC code which is probably best known from its use in CDs.

​

Compare and contrast this with the fact that the new controller uses Bose-Chaudhuri-Hocquenghem (aka “BCH”) for its ECC code; which is a more elegant version that targets individual errors. It is also faster and easier for the controller to correct these errors making for a lowered performance impact. AES encryption has also doubled from 128 to 256

The most important of these new features for consumers is of course the new SATA 6Gb/s capabilities. This larger bus instantly translates into much higher sequential performance. The second generation of flagship SandForce controllers has also received a boost on the small file performance end of things thanks in no small part to a 20% increase in IOPS. The first generation SF1200 was rated for up to 50,000 IOPS whereas the new controller family has a rating of 60,000 IOPS.

The other interesting feature which all but the most basic of the SF2000 models boast is SLC NAND abilities. In the past, a manufacturer had to step up the enterprise SF1500 to get SLC compatibility but now they don't have to. Add in lowered power consumption and you can see that while the SF2000 series builds upon the same basic foundation as the previous generation, they are not all that similar when you take a closer look.

 

[AkG]

A Look at DuraWrite, RAISE and More

A Look at DuraWrite, RAISE and More

Let’s start with the white elephant in the room and explain why this 240GB drive is in reality a 256GB drive. The OCZ Agility 3 has sixteen 16GB NAND chips onboard which gives it a capacity of 256GB, but is seen by the OS as 240GB. Manufacturers use this to help increase IOPS performance and also extend life via wear leveling (as there are always free cells even when the drive is reported as “full”) and even durability since the drive has cells in reserve it can reassign sectors to as the “older” cells die. While 16GB worth of cells set aside for a SandForce drive is not that much compared to some previous models, this is still a lot of space.

​

As we said, over-provisioning is usually for wear leveling and ITGC as it gives the controller extra cells to work with for keeping all the cells at about the same level of wear. However, this is actually not the main reason SandForce sets aside so much. Wear leveling is at best a secondary reason or even just a “bonus” as this over-provisioning is mainly for the Durawrite and RAISE technology.

Unlike other solid state drives which do not compress the data that is written to them, the SandForce controller does real time loss-less compression. The upside to this is not only smaller lookup tables (and thus no need for off chip cache) but also means less writes will occur to the cells. Lowering how much data is written means that less cells have to be used to perform a given task and this should also result in longer life and even fewer controller cycles being taken up with internal house cleaning (via TRIM or ITGC).

​

Longevity may be a nice side effect but the real purpose of this compression is so the controller has to use fewer cells to store a given amount of data and thus has to read from fewer cells than any other drive out there (SandForce claims only .5x is written on average). The benefit to this is even at the NAND level storage itself is the bottleneck for any controller and no matter how fast the NAND is, the controller is faster. Cycles are wasted in waiting for data retrieval and if you can reduce the number of cycles wasted, the faster an SSD will be.

Compressing data and thus hopefully getting a nice little speed boost is all well and fine but as anyone who has ever lost data to corruption in a compressed file knows, reliability is much more important. Compressing data means that any potential loss to a bad or dying cell (or cells) will be magnified on these drives so SandForce needed to ensure that the data was kept as secure as possible. While all drives use ECC, to further ensure data protection SandForce implemented another layer of security.

​

Data protection is where RAISE (Redundant Array of Independent Silicon Elements) comes into the equation. All modern SSDs use various error correction concepts such as ECC. This is because as with any mass produced item there are going to be bad cells while even good cells are going to die off as time goes by. Yet data cannot be lost or the end user’s experience will go from positive to negative. SandForce likes to compare RAISE to that of RAID 5, but unlike RAID 5 which uses a parity stripe, RAISE does not. SandForce does not explicitly say how it does what it does, but what they do say is on top of ECC, redundant data is striped across the array. However, since it is NOT parity data there is no added overheard incurred by calculating the parity stripe.

​

According to SandForce’s documentation, not only individual bits or even pages of data can be recovered but entire BLOCKS of data can be as well. So if a cell dies or passes on bad data, the controller can compensate, pass on GOOD data, mark the cell as defective and if necessary swap out the entire block for a spare from the over-provisioning area. As we said, SandForce does not get into the nitty-gritty details of how DuraWrite or RAISE works, but the fact that it CAN do all this means that it most likely is writing a hash table along with the data.

SandForce is so sure of their controller abilities that they state the chances of data corruption are not only lower than that of other manufactures’ drives, but actually approaches ZERO chance of data corruption. This is a very bold statement, but only time will tell if their estimates are correct. In the mean time, we are willing to give the benefit of the doubt and say that at the very least data corruption is as unlikely with one of these products as it is on any modern MLC drive.

 

[AkG]

Testing Methodology

Testing Methodology

Testing a drive is not as simple as putting together a bunch of files, dragging them onto folder on the drive in Windows and using a stopwatch to time how long the transfer takes. Rather, there are factors such as read / write speed and data burst speed to take into account. There is also the SATA controller on your motherboard and how well it works with SSDs & HDDs to think about as well. For best results you really need a dedicated hardware RAID controller w/ dedicated RAM for drives to shine. Unfortunately, most people do not have the time, inclination or monetary funds to do this. For this reason our testbed will be a more standard motherboard with no mods or high end gear added to it. This is to help replicate what you the end user’s experience will be like.

Even when the hardware issues are taken care of the software itself will have a negative or positive impact on the results. As with the hardware end of things, to obtain the absolute best results you do need to tweak your OS setup; however, just like with the hardware solution most people are not going to do this. For this reason our standard OS setup is used. However, except for the Vista load test times we have done our best to eliminate this issue by having the drive tested as a secondary drive. With the main drive being a Phoneix Pro 120GB Solid State Drive.

For synthetic tests we used a combination of ATTO Disk Benchmark, HDTach, HD Tune, Crystal Disk Benchmark, IOMeter, AS-SSD and PCMark Vanatage.

For real world benchmarks we timed how long a single 10GB rar file took to copy to and then from the devices. We also used 10gb of small files (from 100kb to 200MB) with a total 12,000 files in 400 subfolders.


For all testing a Asus P8P67 Deluxe motherboard was used, running Windows 7 64bit Ultimate edition (or Vista for boot time test). All drives were tested using AHCI mode using Intel RST 10 drivers.

All tests were run 4 times and average results are represented.

In between each test suite runs (with the exception being IOMeter which was done after every run) the drives are cleaned with either HDDerase, SaniErase or OCZ SSDToolbox and then quick formatted to make sure that they were in optimum condition for the next test suite.


Processor: Core i5 2400
Motherboard: Asus P8P67 Deluxe
Memory: 8GB Mushkin DDR3 1300
Graphics card: Asus 5550 passive
Hard Drive: 1x Seagate 3TB XT, OCZ 120GB RevoDrive
Power Supply: XFX 850


SSD FIRMWARE (unless otherwise noted):

OCZ Vertex 2 100GB: 1.33
OCZ Vertex 3 MI 240GB: 2.11
Corsair Force 3 GT 120GB: 1.3
Patriot Pyro 120GB: 3.1.9
Kingston HyperX 240GB: 3.2.0
Crucial M4 256GB: 009
Mushkin Chronos 120GB: 3.2.0
OCZ Agility 3 240GB: 2.11

 

[AkG]

Read Bandwidth / Write Performance

Read Bandwidth

For this benchmark, HDTach was used. It shows the potential read speed which you are likely to experience with these hard drives. The long test was run to give a slightly more accurate picture. We don’t put much stock in Burst speed readings and thus we no longer included it. The most important number is the Average Speed number. This number will tell you what to expect from a given drive in normal, day to day operations. The higher the average the faster your entire system will seem.

​

Sequential read performance was never a strong suit of 120GB ONFi drives and while the 240GB Agility 3 is faster than those drives, it still suffers a bit in this category. The Agility 3 is noticeably slower than what a firmware 009 enabled Crucial M4 256GB model can accomplish.

Luckily, sequential read speed has very little noticeable impact on most real world tasks. To be blunt, this drive is extremely peppy and unless you are routinely transferring massive amounts of large files and using a stop watch it is highly unlikely you will notice a difference of 13 MB/s as this is only a minor difference at most.

Write Performance

For this benchmark HD Tune Pro was used. To run the write benchmark on a drive, you must first remove all partitions from that drive and then and only then will it allow you to run this test. Unlike some other benchmarking utilities the HD Tune Pro writes across the full area of the drive, thus it easily shows any weakness a drive may have.

​

Unlike the sequential read performance of the Agility 3 240GB, the sequential write performance is more than adequate and puts the M4 256GB to shame. With that being said all other SF2281 240GB models we have looked at are faster, but only the Toggle Mode NAND based 120GB Mushkin Chronos Deluxe is able to best this device. Of course, sequential performance tests are the real “slow-pitch softballs” of our tests and we consider these results nothing more than warm up events.

 

[AkG]

ATTO Disk Benchmark

ATTO Disk Benchmark

The ATTO disk benchmark tests the drives read and write speeds using gradually larger size files. For these tests, the ATTO program was set to run from its smallest to largest value (.5KB to 8192KB) and the total length was set to 256MB. The test program then spits out an extrapolated performance figure in megabytes per second.

​

Since the ATTO benchmark plays to the SF2281 controller’s strengths, by using easily compressible data, it is no wonder that the Agility's power curves are extremely good. This is why the various manufactures use it as their de-facto standard test. ATTO does however have a tendency to paint only the most optimal, “rosy” picture possible when dealing with SandForce controllers.

 

[AkG]

Crystal DiskMark / PCMark 7

Crystal DiskMark

Crystal DiskMark is designed to quickly test the performance of your hard drives. Currently, the program allows to measure sequential and random read/write speeds; and allows you to set the number of tests iterations to run. We left the number of tests at 5 and size at 100MB.

​

With its more pessimistic outlook of what the SF2281 controller and ONFi 1 NAND of the Agility 3 can accomplish, Crystal DiskMark shows performance that varies from decent to lackluster by current standards. The only silver lining is the overall performance should be more than enough for most consumers' needs.

PCMark 7

While there are numerous suites of tests that make up PCMark 7, only one is pertinent: the HDD Suite. The HDD Suite consists of numerous tests that try and replicate real world drive usage. Everything from how long a simulated virus scan takes to complete, to MS Vista start up time to game load time is tested in these core tests; however we do not consider this anything other than just another suite of synthetic tests. For this reason, while each test is scored individually we have opted to include only the overall score.

​

After the sub-par Crystal DiskMark numbers, it comes as no surprise to see such low PC Mark 7 numbers. Seeing numbers under 5,000 for a 240GB SF2281 based drive is a new one for us considering the Agility 3's cost. More importantly, since PCMark 7 is a fairly good indicator of real world performance, this does not bode well for our real world tests. Even smaller 120GB models easily outperform the Agility 3 here.

 

[AkG]

AS-SSD / Access Time

AS-SSD

AS-SSD is designed to quickly test the performance of your drives. Currently, the program allows to measure sequential and small 4K read/write speeds as well as 4K file speed at a queue depth of 64. While its primary goal is to accurately test Solid State Drives, it does equally well on all storage mediums it just takes longer to run each test as each test reads or writes 1GB of data.

​

As with most of the synthetic tests we have run so far, the Agility 3 may indeed be better performing than 120GB ONFi 1 drives, but it just can't come close to many other SATA 3 drives we have tested.

Access Time

To obtain an accurate reading on the read and write latency of a given drive, AS-SSD was used for this benchmark. A low number means that the drive’s data can be accessed quickly while a high number means that more time is taken trying to access different parts of the drive.

​

Thanks to it higher density NAND, the Agility 3 240GB is able to once again post numbers that are better than some 120GB SF2281 based drives.

 

[AkG]

Anvil Storage Utilities Pro

Anvil Storage Utilities Pro

Much like AS-SSD, Anvil Pro was created to quickly and easily – yet accurately – test your drives. While it is still in the Beta stages it is a versatile and powerful little program. Currently it can test numerous read / write scenarios but two in particular stand out for us: 4K queue depth of 4 and 4K queue depth of 16. A queue depth of four along with 4K sectors can be equated to what most users will experience in an OS scenario while 16 depth will be encountered only by power users and the like. We have also included the 4k queue depth 1 results to help put these two other numbers in their proper perspective. All settings were left in their default states and the test size was set to 1GB.

​

Once again we are seeing relatively good write numbers but the read results tend to falter a bit.

 

[AkG]

IOMETER

IOMETER

IOMeter is heavily weighted towards the server end of things, and since we here at HWC are more End User centric we will be setting and judging the results of IOMeter a little bit differently than most. To test each drive we ran 5 test runs per HDD (1,4,16,64,128 queue depth) each test having 8 parts, each part lasting 10 min w/ an additional 20 second ramp up. The 8 subparts were set to run 100% random, 80% read 20% write; testing 512b, 1k, 2k,4k,8k,16k,3xk,64k size chunks of data. When each test is finished IOMeter spits out a report, in that reports each of the 8 subtests are given a score in I/Os per second. We then take these 8 numbers add them together and divide by 8. This gives us an average score for that particular queue depth that is heavily weighted for single user environments.

​

When compared against older generation enthusiast grade SSDs or higher end hard drives the OCZ Agility 3 is a great choice since it combines good performance with a good amount of capacity. Unfortunately, when compared against other modern SSDs, it is only barely able to outperform other less expensive ONFi 1 120GB SF2281 drives. In other words, the IOMeter results tend to sum up its results quite nicely.