It's not the size of the SSD that counts--it's the motion (of data) between flash memory and a host computer. While larger SSDs do often offer faster read and write speeds than smaller ones, the memory controller, which manages the flash memory of the SSD and communicates with the computer it's connected to, is the critical component when it comes to performance. Not all controllers are created equal. And LSI, maker of the popular SandForce memory controller, has just announced its third generation controller with a completely new architecture.
SandForce 3700 has been a long time coming. Anandtech writes that they first talked to LSI about the third-gen controller at CES 2012, nearly two years ago. At that point, the controller was very early in development, but over the past two years LSI has nailed down how it wanted to improve upon its SF-2200 controllers with this generation.
First off: the design is modular. "The SF3700 supports both SATA 6Gbps and PCIe 2.0 x4," writes Anandtech. "That's a single silicon offering with support for both interfaces. The interface is selectable during manufacturing at the drive level. End users won't be able to switch between interfaces, but drive makers can quickly shift production between SATA and PCIe drives all with the same silicon...
"The front end, core and back end of the SoC are all modular. Adding support for new types of NVM (e.g. 3D NAND) should be far easier, not to mention the flexibility in adapting to new interface standards. Given that we're in a transition period between SATA and PCIe, modularity on the front end will come in handy as we start looking at interfaces beyond PCIe gen 2."
SF3700's support for SATA and PCIe is great, especially given its speed targets. SATA 3 is currently limited to 6 gigabits per second, although there is a SATA 3.2 revision that will up that speed to 16 gigabits. Until SATA 3.2 actually makes it to market, SF3700's PCIe support will allow for much faster drives than the SATA standard. On the SATA side, SF3700 will top out at 550 MB/s reads and 502 MB/s writes. With PCIe, that number increases to 1800 MB/s reads. And 1800 MB/s writes.
Check out Anandtech's article for more technical details about the new controller. SF3700 includes some updates to existing SandForce technologies, which will improve write performance on lower capacity drives and offer better drive longevity and failure protection. Anandtech notes that LSI hasn't gotten SF3700's performance to their target levels yet--it's currently hitting read speeds of about 1.45 gigabytes per second--but if it does make it up to 1.8 GB/s, it'll be the fastest memory controller around.