Simplfying The SandForce Landscape
As mentioned, we're benchmarking two different SandForce-based drives to help simplify this story a bit. The reasoning here is sound: two SF-22xx-based SSDs of the same capacity will perform almost identically, providing that they both employ the same NAND interface. The thing is, not all vendors use the same NAND, and that's why there is some variation between drives centering on the same controller hardware.
Second-gen SandForce SSDs are available with different flavors of memory, and this is their order of performance, from highest to lowest.
- SandForce with Toggle-mode NAND (i.e. Mushkin Chronos Deluxe, Patriot Wildfire, OCZ Vertex 3 Max IOPS)
- SandForce with Synchronous ONFi NAND (i.e. OCZ Vertex 3, Corsair Force GT, Kingston HyperX)
- SandForce with Asynchronous ONFi NAND (i.e. OCZ Agility 3, Corsair Force 3, Mushkin Chronos, Patriot Pyro)
Toggle-mode and ONFi are simply interface standards, similar to the way FireWire and USB are. They arose from a design disagreement among NAND manufacturers. Intel and Micron back ONFi, while Toshiba and Samsung support Toggle-mode. However, making a simple performance comparison between the two NAND interfaces isn’t easy. Due to the differences in the signaling architecture, it’s not appropriate to compare their peak bandwidth ratings. With that said, Toggle-mode-equipped SSDs commonly top our performance charts, and are some of the fastest SATA drives that we’ve ever tested.
However, SandForce SSDs armed with Toggle-mode memory are virtually nonexistent at the 60 GB capacity point. That’s why we’re limiting our round-up to SandForce SSDs with ONFi-compatible flash. Even within that sub-division there are two varieties: asynchronous and synchronous. Distinguishing between them requires looking up the part numbers silk screened on the package. Intel and Micron make both types of ONFi-compatible flash, so knowing the brand won’t help.
While there are inherent signaling differences that separate the two types of flash found in these smaller SSDs, the key to remember is that synchronous interface is faster. It's also going to increasingly replace cheaper asynchronous memory moving forward. We're testing both memory interfaces to help quantify how much performance variance you might expect to see.
