The difference in available memory comes not only from the ~7% spare area you get from the GB to GiB conversion for moving data around, but also because SandForce specifies an additional 20% flash be set aside for its DuraWrite technology, which is designed to reduce write amplification and extend endurance. Once formatted, the drive only has 93.1GB of usable space. SandForce claims the loss is unavoidable and that this method will eventually have to be adopted by all future solid state drives. The lost capacity increases as the drives become larger. The 200GB model for instance, which has 256GB of flash memory on the PCB, only has 185.5GB of usable storage space. Something else we have found interesting about the Vertex 2 series and the SandForce controllers is that there is no DRAM cache. SandForce is able to do away with the cache by writing less to the flash, meaning there is less data to account for and smaller tables to manage on the fly. Because less data is being written, SandForce claims that manufacturers can use cheaper memory to save on costs. The SF-1200 controller carries a small cache onboard, which is thought to be a few megabytes in size, though the exact figure hasn’t been disclosed. Inside the controller there is also a Tensilica DC_570T CPU core. When we questioned the use of this CPU core, SandForce said it has little to do with the performance of the controller and stated that it is everything else around the CPU that matters. The Vertex 2 features Intel 29F64G08CAMDB flash memory. In total there are 16 chips with 8GB capacity each. OCZ claims maximum read and write performance of 285 and 275 MB/s, respectively, which translates to 14% faster reads than the original Vertex drive and an astonishing 53% faster writes. The drive uses a slim 2.5" design measuring 99.8 x 69.63 x 9.3mm and weighing under 100 grams. OCZ is shipping these new Vertex 2 drives with a 3.5" bay adapter for easier installation in a desktop computer. The drive is said to use 2 watts of power when in use and 0.5 watts in standby. You can set these up to work in RAID if you were to purchase more than one. Finally, OCZ backs the Vertex 2 with a 3-year warranty.
