A-DATA announced today the introduction of what it calls the “industry’s fastest” solid state disk.
The new lineup of SSDs bear the S596 moniker and will debut in 64GB, 128GB and 256GB varieties. In terms of features, the drive features an unknown controller–though Indilinx is a likely candidate–and a DDR2 DRAM cache to push sequential reads/writes up to 250MBps and 180MBps, respectively. While these speeds are mighty quick, they are not the “industry’s fastest” as A-DATA claims. Instead, drives like the OCZ Vertex EX and Patriot KOI offer faster read and writes. It is still possible that the drive is the industry’s fastest if judged strictly by IOPS, but the firm has not published that data, making it a peculiar metric to stake their claims on.
Rounding out the show, the S596 offers a mini USB port for external connectivity and support for the ATA TRIM command, which means it has earned a place on our growing list of TRIM-enabled SSDs.
What is ATA TRIM?
An SSD’s total size is composed of thousands of smaller units called “blocks,” which average about 512k these days. SSDs deliberately try to spread written data across all of these blocks so as not to prematurely wear out the memory chips, which can only accept a limited number of writes. This technique is called wear leveling. Over time, wear leveling guarantees that every block on the SSD will receive a write of data at one time or another. When this is combined with Windows’ delete mechanism which only marks space as free, rather than physically removing the data, an SSD is guaranteed to get gummed up with a hodgepodge of deleted and undeleted files. When the SSD’s physical cells are full, regardless of the displayed free capacity, the drive must perform a complicated routine called the read/erase/modify/write cycle to store new data.
An REMW cycle forces an SSD to scan its blocks for deleted but unpurged files, copy active data to cache, purge the deleted files, append the new data to the data in cache, and then write the cache back to the new free space. This is called write amplification, and in serious cases, it can force an SSD to shuffle up to 20GB of data just to write 1GB of new information. This causes significant performance issues for SSDs.
The solution to this problem is to let SSDs physically erase files the moment they are deleted in the OS, and that is precisely what the TRIM command does. Windows 7 and Windows Server 2008 R2 are the only Microsoft OSes that supports it, and the feature cannot be used without support from both the drive’s controller and firmware.
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