When SandForce unleashed their SF-1000 series of SSD controllers we never imagined they would be as widely received as they were. Countless manufacturers got onboard such as ADATA, Apacer, Corsair, G.Skill, Mushkin, OCZ, Patriot, Silicon Power, Super Talent and the list just goes on.

Therefore it came as little surprise when the second generation SF-2000 series became the most widely used SSD controllers after being announced in early 2011. The consumer-level performance controller, known as the SF-2200 (aka SF-2281), includes support for the SATA 6Gb/s interface while boasting read and write speeds of 500MB/s+, a mind blowing figure when compared to the previous generation chip.

Already there are more than a dozen manufacturers that have adopted the new SF-2200 controller, with the most renowned likely being OCZ. However there are numerous high-quality alternatives, and today's comes from memory maker ADATA.

ADATA was amongst the first to implement the SandForce SF-1200 controller back in March of 2010, when they announced the S599 series. Featuring drives with capacities of 40GB, 60GB, 120GB and even 240GB, the S599 series was competitively priced. They even kept on top of firmware updates, with the most recent coming in April of this year.

Although the naming scheme is a little confusing, ADATA’s latest generation SandForce series is called S511 and features 60GB, 120GB, 240GB and 480GB models. Again ADATA has been very diligent when it comes to firmware updates, with their latest update being released this month. The version 3.2.0 release fixes the BSOD (Blue Screen Of Death) issue that has been plaguing all SandForce SF-2000 series SSDs.

This is a major fix for the second generation SandForce drives, and it means that those who have been holding off can now finally buy with confidence. Priced at $428 the ADATA S511 240GB is a costly investment. That said, when compared to the competition that price is surprisingly low, as the Kingston HyperX 240GB costs $470 while the OCZ Vertex 3 240GB is slightly more expensive again at $475.

The 60GB model packs read and write speeds of 550MB/s - 500MB/s, while the larger 120GB version is slightly faster with 550MB/s reads 510MB/s writes. The 240GB model is slightly faster again as the write performance is boosted to 520MB/s. The largest model offers 480GB of storage and is actually the slowest, rated at 540MB/s reads and 460MB/s writes.

Naturally, using the SATA 6Gb/s interface is essential to achieving those speeds. Currently Intel's Sandy Bridge platform provides native SATA 6Gb/s support, as does AMD’s AM3+ platform.

There are also third party embedded solutions, such as the Marvell 88SE9128, which can provide motherboards with SATA 6Gb/s support, but offer very poor results compared to Intel's implementation. That said, there is a new Marvell 88SE9182 controller that can mimic the performance of Intel's 6 series chipsets, so support for the 6Gb/s SATA is improving.

All four S511 models are loaded with MLC NAND (25nm) flash memory. Our review sample has sixteen 16GB Intel 29F16B08CAME1 NAND ICs for a total capacity of 256GB. The reason this is marketed as a 240GB SSD is because 16GB is reserved for data parity (8GB for RAISE), garbage collection, and block replacement.

Once formatted in Windows, the original 240GB is converted to 224GiB, though Windows shows this as 224GB, so it seems like 7% of the original capacity has been lost. With an MSRP of $428, the S511 240GB costs a mere $1.78 per gigabyte, which is amazing value for a high-performance SSD.

Like the original SF-1222 controller, the second-generation SF-2281 uses data compression technology called DuraWrite. This technology is designed to help lower write amplification and extend the drive's life by using fewer program-erase cycles. The upside is that this doesn't require a memory buffer, while the downside is that it uses more storage space on the drive.

The same Tensilica DC_570T CPU we mentioned in our Vertex 2 review is being used in the SF-2281. Although the CPU remains the same, the compression engine has improved. The second-generation SandForce controllers have a bigger block of silicon dedicated to DuraWrite technology, while the garbage collection algorithms have also been improved.

ADATA has given the S511 the same one-million-hour MTBF (Mean Time Between Failure) rating as the S599 series. This figure essentially means nothing to the consumer and we really have no idea how reliable these drives are going to be in the very long run.

However, the S511’s three-year warranty should let customers sleep comfortably at night knowing they're covered for a reasonable timeframe. We'd like to drop a friendly reminder here that this won't protect your data, so be diligent about backups.

Hardware - Intel Core i7-2600K (LGA1155) - x2 4GB DDR3-1600 G.Skill (CAS 8-8-8-20) - Samsung Spinpoint F1 1TB 7200-RPM (Serial ATA 3Gb/s) - Asus GeForce GTX 580 (1536MB) - Asus P8P67 Deluxe (Intel P67) - OCZ ZX Series (1250w) Software - Microsoft Windows 7 Ultimate (64-bit) - Nvidia Forceware 280.26

In addition to our featured storage devices, the Hitachi Deskstar 7K1000.C 1TB 3.5" 7200-RPM hard drive has been included for comparison purposes.

For comparison purposes we have included SSDs using a wide range of different controllers. Our testing suite consists of four synthetic benchmark programs and our own file copying and load time tests.

As you should know by now, the problem with testing SSDs is that while the manufacturer claims impressive peak I/O performance out of the box, this performance can diminish over time. Unlike a conventional hard drive, any write operation made to an SSD is a two-step process, first the data block must be erased and then written to. Obviously if the drive is brand new and unused there will be nothing to erase and therefore the first step can be bypassed, but this only happens once unless the drive is trimmed.

In consideration of this, we will test how much performance you can expect to lose from each SSD over time. We will test all drives in their clean unused state and then run the HD Tach full benchmark several times, which fills the entire drive. This simulates heavy usage and gives us a clear indication of how performance will be affected in normal long-term use.

Having said all that, all drives support the Windows 7 TRIM function, which is meant to counteract these negative effects in the long run, so it will be interesting to see how the drives perform against each other.

The file transfer performance of the ADATA S511 240GB in our 6GB single file test was impressive, beating all previously tested SandForce SF-2200 drives. With a throughput of 165.8MB/s the S511 240GB came second only to the Samsung 830 512GB SSD. Meanwhile it was 5MB/s faster than the OCZ Vertex 3 Max IOPS 240GB and 7MB/s faster than the Kingston HyperX 240GB.

The program copy performance was just as impressive, with the ADATA S511 240GB providing a throughput of 187.8MB/s which was just 8MB/s slower than the OCZ Vertex 3 240GB and 3MB/s faster than the Samsung 830 512GB.

Although the ADATA S511 240GB did fall behind the OCZ Vertex 3 240GB by a 17MB/s margin, it was able to match the Kingston HyperX 240GB with a throughput of 173.1MB/s.

The ADATA S511 240GB performed very well in our Windows 7 boot time test, taking just 9.6 seconds. This was roughly the same time recorded when using the Kingston HyperX 240GB, while it was a fraction slower than the OCZ Vertex 3 Max IOPS 240GB SSD.

The Windows 7 multi-tasking performance was also very good, as the ADATA S511 240GB took just 5 seconds to complete the task, matching the performance of the Kingston HyperX 240GB.

When loading Adobe Photoshop CS4 the ADATA S511 240GB was as quick as any SSD tested to date, taking just 1.2 seconds.

Finally when loading the StarCraft II level the ADATA S511 240GB was just half a second slower than the OCZ Vertex 3 240GB, while it matched the performance of the Kingston HyperX 240GB.

The ADATA S511 240GB performed well in the CrystalDiskMark sequential read and write performance tests, as it was slightly faster than the Vertex 3 240GB, making it one of the fastest SSDs tested.

The random 512K performance was just as impressive and again the ADATA S511 240GB was found to be faster than the OCZ Vertex 3 240GB.

Interestingly the random 4K-QD32 read performance was quite slow with a throughput of just 215.9MB/s, while the Vertex 3 240GB managed 292.7MB/s. The write performance on the other hand was much stronger as the S511 240GB achieved a throughput of 239.2MB/s, making it just a fraction slower than the Kingston HyperX 240GB.

The Atto Disk Benchmark read performance of the ADATA S511 240GB was typical for that of a SandForce SF-2200 based SSD, as it closely matched the performance of the OCZ Vertex 3 240GB and Kingston HyperX 240GB. The drive maxed out a 474MB/s when testing with 128K sample data.

The write performance of the ADATA S511 240GB was also typical for that of a second generation SandForce SSD. Here we find the S511 240GB hitting a maximum of 504MB/s for the 128K test.

After many months of users complaining about the BSOD/disconnect issue with SF-2200 based SSDs, it seems SandForce has finally found a fix. For those like ADATA that use the standard SandForce numbering scheme for firmware updates, the 3.2.0 version that we tested with carries the fix.

Throughout the testing phase we did not run into a single stability issue with the ADATA S511, and having used the drive in my primary system for a month now I am happy to say it has been smooth sailing.

The real-world performance of the S511 240GB was impressive as the drive performed well in both our file copy and application tests. The only weakness found was when running the CrystalDiskMark random 4K-QD32 test, where the read performance was considerably lower than the OCZ Vertex 3 240GB and Kingston HyperX 240GB drives.

Whereas the Vertex 3 240GB and Kingston HyperX 240GB use Micron 29D128G08CFAAB memory, ADATA went with Intel 29F16B08CAME1 for the S511 240GB, the same memory used by the Corsair Force Series GT 240GB drive. This memory seems to give slightly better top-end performance, but perhaps sacrificing some of the low-down performance could be a result of this.

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In any case, the ADATA S511 was fast and more importantly it is very competitively priced. When compared to the $475 asking price of the OCZ Vertex 3 240GB, the S511 seems like a bargain at just $428 and really it is. That said, the Corsair Force Series GT 240GB is slightly cheaper at $410, so at this point Corsair is managing to slightly undercut ADATA.

Overall we have been pleased with how the ADATA S511 240GB drive has performed in our benchmarks and in terms of stability. For those seeking a well-supported SSD that delivers excellent performance utilizing the latest SATA 6Gb/s interface, we suggest you give the S511 series a close look.