SandForce SF1500 Solid State Drive

Since their retail introduction at the 2008 Consumer Electronics Show, Solid State Drives have been at the center of my attention. In just two short years, the entire SSD market has recreated itself several times over. Counting the generations of SSD processors has become difficult for experienced experts, and keeping-up with architecture has come with its own challenges. Benchmark Reviews has tested dozens of Solid State Drive controllers, and we've seen everything from dual-SATA controllers in RAID-0 to large cache buffer modules. In this article Benchmark Reviews inspects the SandForce SF1500 Solid State Drive architecture, which is used in the (now-cancelled) OCZ Vertex-2 Pro MLC SSD.

As of January 2010 several major companies offer Flash NAND SSD controllers. with many more in development. The most popular consumer controllers are: Indilinx IDX110M00-FC "Barefoot", Intel PC29AS21AA0, JMicron JMF612, Samsung S3C29RBB01-YK40, Toshiba T6UG1XBG and Marvell 88SS8014-BHP2. OCZ and others hope to add the SandForce SF-1500 controller onto this list very soon.

During the 2010 Consumer Electronics Show, it seemed like manufacturers were desperately racing to be the first company to launch a SandForce-based SSD. Retail leaders have already projected Q1-2010 product availability, and at least one company has already built marketing brochures claiming that they are the first with a SandForce-based SSD product on the market. Fortunately, OCZ is a company that doesn't launch vaporware and waits for samples to be in-hand before issuing a press release. Despite all of the hype, Benchmark Reviews was able to walk away from CES with a working product sample from OCZ... who will probably be the first company to have the SandForce SSD to market... for real.

Our SandForce SF-1500 SSD processor board was taken from the OCZ Vertex-2 Pro SSD engineering sample. The Vertex-2 Pro shares the same SandForce processor and layout as the upcoming Vertex-2 and Vertex-2 Pro EX models, so this article should cover the entire Vertex-2 series; with exception to flash NAND parts which may differ between models.

From the top-view image above, it doesn't look like there's anything dramatically innovative on the SandForce Solid State Drive. Eight flash NAND modules make a horseshoe around the SandForce SF-1500 SSD processor, and plenty of electronics fill in the remaining space atop the printed circuit board. Once the SandForce SSD board is turned to expose the underside, the difference is obvious: SandForce has used their DuraClass technology to remove the DRAM buffer and incorporate a flat-capacitor to retain data.

The SandForce SF-1565TA2-SBH processor is part of their SF-1500 family of SSD controller chips, and SSDs will utilize either the SF-1200 processor for retail consumers or SF-1500 for enterprise devices. All SandForce SSD controllers offer native TRIM support in Windows 7.

SF-1500 SSD Processors provide superior ECC data protection and include SandForce's unique RAISE (Redundant Array of Independent Silicon Elements) technology. RAISE provides the protection and reliability of RAID on a single SSD drive, thanks to flash architecture, without the significant write overhead of parity. The SandForce DuraClass technology automatically stores data in AES-128 encrypted format, preventing data extraction directly from the physical flash memory modules.

The brand of internal NAND flash memory used in SSDs is usually a decision left up to the OEM, although our test sample (OCZ Vertex-2 Pro) utilized Micron MT29F64G08CFABAWP IC parts. These lead-free RoHS-compliant 48-pin ICs use multi-layer cell 64Gb density, and require 3.3V per module.

The real twist in SandForce's design is the large Cap-XX HZ202, which is a dual-cell flat capacitor that stores 0.09 farad at 5.5 volts. The extra power reserve is necessary to enable SandForce 'DuraClass' technology, a feature that ensures write commands are completed from the power stored in the super-capacitor included on Enterprise-only products. It's an insurance policy that guarantees data integrity on sudden power loss, and allows the last write does to complete so no data is lost. The Vertex-2 Pro will be the first high-performance enterprise SSD to offer this feature, and will be exclusive to their Enterprise-specific models and not retail enthusiast products.

Another benefit of SandForce's architecture is that the SSD keeps information on the NAND grid and removes the need for a separate cache buffer DRAM module. The result is a faster transaction, albeit at the expense of total storage capacity. The 128GB model measures only 100GB once formatted, with an estimated 20GB dedicated to transaction space.

EDITOR'S NOTE: OCZ Technology will not produce the OCZ Vertex-2 Pro as previously planned. They have instead produced the OCZ Vertex-2 Limited Edition.

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