Page 2 - A Closer Look, Installation, Test System
Since there probably is not too much we can write about a solid state drive -- especially when it comes to the physical aspect of it -- let us quickly cover it before we move onto the technical aspects and benchmark results. The OCZ Agility 3 is pretty much identical in appearance to the OCZ Vertex 3, with the exception of the sticker in the middle, which is now modified with a green rather than silver color scheme. It features an aluminum housing to enhance heat dissipation, with a side benefit of being incredibly lightweight for what you get. On top of the textured matte black finish is a large label across the center to ensure the user will make no mistake that this is an OCZ Agility 3 drive. Measuring in at 99.8 x 69.63 x 9.3mm, these are pretty much standard dimensions for a 2.5" internal drive. It is also quite lightweight, with a manufacturer's specification of 77g. OCZ Agility 3 drives will have no problems fitting into your laptop hard disk bay if you want to boost mobile computing performance, but if you want to use it in your desktop and your chassis has no 2.5" mount, then you will need to find your own solution. Fortunately, most modern cases have 2.5" drive bays anyway, so that should not be too much of a concern.
Turning the SSD around reveals a familiar metal backplate -- except this time, there is no exposed printed circuit board like you would normally see with a traditional hard disk drive. The only thing that is common between the Agility 3 SSD and a traditional hard disk drive is its SATA 6Gb/s and corresponding power connector at the end. As shown in our photo above, you will find a large label with the usual series certification logos and warning statements, along with information on drive model and capacity. In case you missed it, our particular unit is the OCZ Agility 3 240GB, haha. The smaller adjacent label with a barcode has the SSD's part number and serial number printed on it. As with all OCZ SSDs, they are all made in Taiwan, and this one is no exception.
The OCZ Agility 3's shell is attached to the metal backplate by four small screws. One of the screws has a warranty seal over it, so in order to take a peek inside the SSD, you will have to inevitably void your warranty. Therefore, to save you some trouble, I cracked mine open to take some photos of its internals for you to see. And by doing so, it is unsurprising to find how simple an SSD is inside compared to a traditional HDD -- it makes you almost wonder they cost would an arm and a leg to the end user (Yes, I understand NAND flash chips are still quite costly, haha). It is really nothing complicated -- just a small OCZ designed green printed circuit board, and that's it. Of course, there is more than what that meets the eye. The heart of OCZ's Agility 3 is the new SandForce SF-2281 controller. As the drive controller is fundamentally very important to any SSD, what makes it so special is that it is capable of doing real time data compression to make extremely fast I/O performance possible without the need of external cache memory.
The second generation SandForce controller used in the OCZ Agility 3 240GB has been updated in several areas. Other than the obvious performance increases -- we will have lots of time to talk about that in just a second -- major updates include on-the-fly data encryption using a 256-bit AES algorithm, rather than an 128-bit AES algorithm by its predecessor. This cannot be disabled, but it lacks a password by default; it therefore functions as an unencrypted storage unit to the end user. As with the SF-1222, the SF-2281 also focuses on increased wear performance as part of the DuraWrite scheme. This has also been updated with better Error Correcting Code, or ECC. In the past, SandForce controllers used the Reed-Solomon algorithm -- it works well for correcting scattered errors, but has a high processing overhead, and therefore does not work very well for correcting concentrated errors. To overcome this problem, it is replaced by the Bose-Chaudhuri-Hocquenghem algorithm. Other than improved efficiency due to its straightforward implementation, it also works well in correcting both scattered and concentrated errors across the drive.
SandForce's DuraWrite system is especially beneficial to multi-level cell (MLC) based flash drives like the OCZ Agility 3. Unlike single level cell (SLC) flash memory, MLC flash memory stores four states, or two bits, per cell. It is cheaper to manufacture; unfortunately it also has significantly less write cycles before it wears out -- not to mention flash memory comes in different grades. There are two main ways to resolve this problem. The first one is to use a technique called wear leveling. Wear leveling manages data in a way that erasures and rewrites are evenly spread out across the drive, so not a single area experiences a high concentration of write activity. Secondly, unlike traditional magnetic hard drives, data cannot be directly overwritten in the world of flash memory. The write area must first be erased before new information can be written. This brings onto the topic the second technique, which relates to a phenomenon called write amplification. Write amplification is calculated by the data written to the flash memory divided by the data written by the host. Optimally, you will want this number as low as possible -- and it is probably makes sense to think the lowest value possible is 1. That is, until the SandForce controller rolled along earlier this year and changed the rules of the game. By doing on-the-fly compression, this results in a write amplification of an astonishing low value of 0.5 according to the company. Intel SSDs have a write amplification of 1.1, and magnitudes as high as 10 are not out of the ordinary in the industry.
As aforementioned, pages of flash memory need to be first erased before it can be written to again. Traditional magnetic hard drives do not exhibit this characteristic, so normally when you hit the delete button, the operating system simply marks the corresponding data blocks as free with the data still physically intact. All this means is new data is permitted to overwrite existing data in that area. This poses a problem for solid state drives, because it will significantly decrease write performance if the user needs to wait for the system to clear an area before new data can be written. With native TRIM support, it allows the operating system to tell the SSD which blocks of data are no longer needed. The SSD can then do garbage collection overhead, and make it available for new data to be directly written without delay. OCZ's Agility 3 SSD has native TRIM support, but it will not work once you pair it with another drive in RAID. This is no different than any other solid state drive in the market today.
Lastly, the new SandForce SF-2281 controller has updated toggle-mode and ONFi 2.2 flash memory support in conjunction with processor power throttling. The former improves compatibility with different flash memory for improved NAND supplier flexibility for the drive manufacturer; whereas the latter increases power efficiency like SpeedStep on your desktop CPU. All in all, the SandForce SF-2281 controller does have a small microprocessor and a few undisclosed megabytes of memory inside to handle all the dirty work -- but with the elimination of the external cache, SandForce based SSDs have unprecedented random read and write performance. This adds on to the already excellent sequential data rates across the board makes it a winning combination -- but we're not talking about just about just barely edging out SF-1222 drives in benchmarks. What we are talking about here is rated performance of an smashing 525MB/s max read, 500MB/s max write, and up to 85,000 input/output operations per second (This is up from the SF-1222 based Vertex 2's figures of 285, 275, and 50,000, respectively). That's pretty much almost doubling the Vertex 2's performance at neck breaking, pants peeing speed. Compared to the OCZ Vertex 3 Max IOPS 240GB, the maximum read rating is down 25MB/s. But is that all the difference? This is why benchmarking this drive is actually very exciting. Oh yeah, you will need a SATA 6Gb/s port, and you will want a native Intel one while we are at it.
A total of 16 NAND flash chips are found on the OCZ Agility 3 solid state disk, with 8 on each side. The chips used are Micron 29F128G08CFAAA asynchronous flash memory, with a capacity of 16GB per integrated circuit chip. These are multi-level cells manufactured on the 25nm fabrication process. 16GB out of the 256GB total capacity (Just under 7%) is provisioned for the SandForce drive controller for garbage collection and wear leveling algorithms, so the actual usable space is 240GB, as advertised. You will see 223GB in Windows. This is a small amount compared to other SandForce based SSDs; which can range anywhere from 7% to 28% in 34nm units for what the company refers to as Redundant Array of Independent Silicon Elements, or RAISE. SandForce claims RAISE is similar to a RAID 5 array within the drive that redundant data can be used to recover entire pages of corrupt or lost data within the drive, should problems arise with its memory cells over time. This is implemented in conjunction with a powerful error correction system and cyclic redundancy check protection to improve its uncorrectable bit error rate.
Our test configuration as follows:
CPU: Intel Core i5-2500K @ 4.50GHz (Overclocked, Turbo Boost disabled)
CPU Cooling: Noctua NH-D14
Motherboard: ASUS P8P67 WS Revolution
RAM: G.SKILL Ripjaws F3-12800CL7D-8GBRH 2x4GB @ DDR3-1600 7-8-7-24 (Stock frequency @ stock latencies)
Graphics: Gigabyte Radeon HD 6870 1GB SOC
Chassis: Cooler Master 690 II Advanced NVIDIA Edition (Noctua NF-S12B FLX, NZXT Sleeved LED Kit)
Power: NZXT HALE90 750W
Sound: Auzentech X-Fi HomeTheater HD
Optical Drive: LiteOn iHAS224-06 24X DVD Writer
Operating System: Microsoft Windows 7 Professional x64
1. Introduction and Specifications
2. A Closer Look, Installation, Test System
3. Benchmark: ATTO Disk Benchmark
4. Benchmark: Crystal Disk Mark 3.0
5. Benchmark: AIDA64 Disk Benchmark
6. Benchmark: HD Tach 220.127.116.11
7. Benchmark: HD Tune Pro 4.60
8. Benchmark: PassMark PerformanceTest 7.0
9. Benchmark: PCMark Vantage
10. Laptop Usage and Conclusion