|Introduction and Specifications|
|The SSD market is very competitive at the moment, to say the least, and though ADATA isn’t always necessarily front and center, the company has a handful of interesting product offerings, including the ADATA XPG SX900 we'll be showing you here.
SSD manufacturers sometimes roll with proprietary controllers, such as OCZ and Samsung, while others adopt third-party products. ADATA falls into the latter category. The XPG SX900 packs an LSI SandForce 2281 controller, which is one of the more popular solutions at this time.
ADATA says that its firmware actually increases the available storage capacity slightly over other SandForce-based drives, giving the XPG SX900 about 7% more available storage capacity. Simply put, SandForce controllers set aside a small amount of flash storage to use for over provisioning and other management functions, which is designed to offer better performance and endurance, but there’s now a way to essentially give the user back that small percentage of reserved storage capacity--presumably without negatively impacting the drive in regard to performance and endurance. ADATA’s XPG SX900 was one of the first drives to feature the new capability.
In fact, the XPG SX900 has actually been out for a while now, but the version we tested is a little different. For one thing, earlier versions had 25nm IMFT NAND chips on board, while later versions had repackaged 20nm NAND. Our SSD though has 19nm SanDisk flash chips inside. This drive also has updated firmware (version 5.0.7a) that should smooth out any issues earlier XPG SX900s may have had.
ADATA is putting out XPG 900s in several capacities, including 64GB, 128GB, 256GB, and 512GB, and we gave the 256GB version a spin. The 256GB version, it turns out, has the best specifications in terms of speed in the whole line; ADATA claims that it can hit read/write speeds of 550MBps/530MBps (in ATTO) and 500MBps/320MBps (in AS-SSD) with max 4K write IOPs of 91K.
Earlier batches of the XPG SX900 had full-length PCBs, but as you can see, this one is a shorty. Even so, ADATA managed to fit sixteen 19nm SanDisk flash chips (eight on each side), along with the SandForce controller.
The Z-height of this drive is just 7mm, and the chassis has a dark, brushed metal top and bottom with a silver brushed metal band around the edge. Also note the included mounting bracket that allows a user to insert the drive in a 3.5-inch bay on a desktop.
The “XPG” is the product name is for “Xtreme Performance Gear”; let’s take a look at some benchmarks to see just how "extreme" this drive’s performance really is.
|Test Setup, IOMeter 1.1 RC|
|Our Test Methods: Under each test condition, the Solid State Drives tested here were installed as secondary volumes in our testbed, with a standard spinning hard disk for the OS and benchmark installations. Out testbed's motherboard was updated with the latest UEFI available as of press time and AHCI (or RAID) mode was enabled. The SSDs were secure erased before testing and left blank without partitions wherever possible, unless a test required them to be partitioned and formatted, as was the case with our ATTO, PCMark 7, and CrystalDiskMark benchmark tests. Windows firewall, automatic updates and screen savers were all disabled before testing. In all test runs, we rebooted the system, ensured all temp and prefetch data was purged, and waited several minutes for drive activity to settle and for the system to reach an idle state before invoking a test.
As we've noted in previous SSD articles, though IOMeter is clearly a well-respected industry standard drive benchmark, we're not completely comfortable with it for testing SSDs. The fact of the matter is, though our actual results with IOMeter appear to scale properly, it is debatable whether or not certain access patterns, as they are presented to and measured on an SSD, actually provide a valid example of real-world performance for the average end user. That said, we do think IOMeter is a reliable gauge for relative available throughput within a given storage solution. In addition there are certain higher-end workloads you can place on a drive with IOMeter, that you can't with most other storage benchmark tools available currently.
In the following tables, we're showing two sets of access patterns; our custom Workstation pattern, with an 8K transfer size, 80% reads (20% writes) and 80% random (20% sequential) access and another with 4K transfers, 100% random, 100% writes.
The ADATA drive scored in the middle of the pack with the IOMeter default access test, but it is worth noting that it was by far the most consistent in terms of IOPS as the number of concurrent I/Os increased. In our custom workstation test, the XPG SX900 followed a similar shape as the rest of the field, but as the concurrent I/Os increased, it nudged past the other contenders and finished with the highest IOPS of the group.
In terms of total MBps, it also scored the best overall in the workstation test while posting a solid but unspectacular score in the default test.
|SiSoft SANDRA 2013|
|Next we ran SiSoft SANDRA, the the System ANalyzer, Diagnostic and Reporting Assistant. Here, we used the Physical Disk test suite and provided the results from our comparison SSDs. The benchmarks were run without formatting (which is a requirement for the write test) and read and write performance metrics are detailed below.
In SANDRA, the XPG SX900 delivered the top read score, narrowly edging out the OCZ Vertex 450, but in the write test, it evinces some of the same relatively weak speeds as some other SandForce drives.
|ATTO Disk Benchmark|
|ATTO is another "quick and dirty" type of disk benchmark that measures transfer speeds across a specific volume length. It measures raw transfer rates for both reads and writes and graphs them out in an easily interpreted chart. We chose .5kb through 8192kb transfer sizes and a queue depth of 6 over a total max volume length of 256MB. ATTO's workloads are sequential in nature and measure raw bandwidth, rather than I/O response time, access latency, etc. This test was performed on blank, formatted drives with default NTFS partitions in Windows 7 x64.
Although our ADATA drive was a mite slow out of the gate in the write throughput test, it hung with the lead dogs in larger transfer sizes, starting at about 32KB. By the end of the read test, the XPG SX900 was part of the top cluster of scorers, although between 4KB and 64KB transfer sizes, non-SandForce controllers outpaced its performance for the most part.
|HD Tune Benchmarks|
|EFD Software's HD Tune is described on the company's web site as such: "HD Tune is a hard disk utility with many functions. It can be used to measure the drive's performance, scan for errors, check the health status (S.M.A.R.T.), securely erase all data and much more." The
The XPG SX900 offered up mediocre performance in HD Tune. Its only particularly strong score was the Average Transfer Rate read test, and its read score in the Burst Rate test wasn’t bad. However, across the board, it posted midrange scores, though access times were a bit high relative to the competition.
|CrystalDiskMark is a synthetic benchmark that tests both sequential and random small and mid-sized file transfers using incompressible data. It provides a quick look at best and worst case scenarios with regard to SSD performance, best case being larger sequential transfers and worse case being small, random transfers.
SandForce-based SSDs tend to do well in CrystalDiskMark, and wouldn’t you know it, the XPG SX900 fit the profile. It actually posted essentially the best scores in both read and write tests in the 512K data test (we’ll call it a virtual tie with the OCZ Vertex 450’s write score) as well as the 4K transfer test’s read score and the 4K QD32 write score.
|AS-SSD Compression Test|
|Next up we ran the Compression Benchmark built-into AS SSD, an SSD specific benchmark being developed by Alex Intelligent Software. This test is interesting because it uses a mix of compressible and incompressible data and outputs both Read and Write throughput of the drive. We only graphed a small fraction of the data (1% compressible, 50% compressible, and 100% compressible), but the trend is representative of the benchmark’s complete results.
Speaking of predictable SandForce performance, those SSDs typically struggle with incompressible data, and ADATA hasn’t managed to firmware-update itself away from that problem with the XPG SX900. This is a performance characteristic of all current-gen SandForce controllers, which won't be going away.
|PCMark 7 Storage Benchmarks|
|We really like PCMark 7's Secondary Storage benchmark module for its pseudo real-world application measurement approach to testing. PCMark 7 offers a trace-based measurement of system response times under various scripted workloads of traditional client / desktop system operation. From simple application start-up performance, to data streaming from a drive in a game engine, and video editing with Windows Movie Maker, we feel more comfortable that these tests reasonably illustrate the performance profile of SSDs in an end-user / consumer PC usage model, more so than a purely synthetic transfer test.
If you want to judge an SSD based on its performance in more real-world situations, PCMark 7 gives ADATA reason to celebrate, because the XPG SX900 rocked it. It bested the field (by a hair) in the Secondary Storage test, and it has the top scores in every sub test except for the Importing Pictures test, where the Corsair Force GT edged it out by 0.05 of a point.
|Our Summary and Conclusion|
|Performance Summary: The ADATA XPG SX900’s performance was very good, if somewhat uneven. On the one hand, it posted best-in-class scores in PCMark 7 and did very well in ATTO and (for the most part) in CrystalDiskMark tests. Its HD Tune scores, by contrast, were inconsistent, and it had trouble with some write tests as well as the IOMeter default access pattern. Overall though, the performance of the ADATA XPG SX900 is among the best of the SandForce-based drives we've tested.
The ADATA XPG SX900's performance profile is typical of SandForce 2281 based drives, with the one caveat that this SSD has freed up the extra storage capacity that was traditionally over-provisioned. One other thing the ADATA XPG SX900 definitely has going for it is price. As of this publication, this drive costs $199.99 (street price), and with a formatted capacity of 238GB, that’s just $0.84 per GB, which is very competitive.
Considering the drive’s performance--which is occasionally very high despite the inconsistencies--the low price makes the XPG SX900 a good deal.
However, a word of caution: The drive has been out for more than a year, and as we’ve mentioned, it’s been built with at least three different types of NAND, it has at least two differently-sized PCBs (depending on the stepping), and it’s come in two different z-heights (9.5mm and 7mm), so you might want to check model and revision numbers. Regardless which iteration of the SSD you end up with, make sure you have the latest firmware update for the drive.
When you drop down your money, make sure you’re buying one of the newer versions. Scan those spec sheets with an eagle eye.