SSD Flash Controller

Every SSD includes a controller i.e. an embedded processor that executes firmware-level code and is one of the most important factors of SSD performance.

Functions:

1. Error correction (ECC)
2. Wear leveling
3. Bad block mapping
4. Read scrubbing and read disturb management
5. Read and write caching
6. Garbage collection
7. Encryption

Sandfore Controller

SandForce initially released the SF-1000 family of SSD Processors and split them into enterprise and client computing applications. The SF-1500 was the enterprise product and the SF-1200 the client focused product.

 In October 2010, SandForce introduced their second generation SSD controllers called the SF-2000 family focused on enterprise applications. Enhancements included: SATA 3.0 (6 Gbit/s), faster speeds, security, and data protection features. The client version of this second generation line was introduced in February 2011 with most of the same enhancements seen in the SF-2500.

Launched in November 2013, the SF 3700 family of controllers supports triple-level cell flash for high-capacity drives and NVM Express for improved performance at the high end. Sample engineering boards with the PCIe x4 (gen 2) model of this controller found 1,800 MB/sec read/write sequential speeds and 150K/80K random IOPS. A Kingston HyperX "prosumer" product using this controller was showcased at the Consumer Electronics Show 2014 and promised similar performance.Mushkin also showcased products using the SF 3700 series at CES, highligting their M.2 Helix series up to 480GB (512GiB) and up to 2TB in for the 2.5 inch format.
The SF 3700 family consists of the following announced models:
SF3719 — SATA 6Gbit/s + x2 PCIe; "entry level" product with identical connectivity but announced to have fewer firmware features than the "mainstream" SF3729; precise differences in features not yet disclosed
SF3729 — SATA 6Gbit/s + x2 PCIe
SF3739 — x4 PCIe (gen 2); support for optional battery or supercapacitor “full power fail” protection
SF3759 — “full enterprise feature set” (no further details released yet)


All these models are actually made of the same die (produced in a 40 nm process), an area of which goes unused in the lower-end products. The RAISE technology in the SF 3700 series was upgraded from protecting against a single page or block failure (in the previous series) to "multiple pages and blocks or up to a full die" with the so-called RAISE level 2. Additionally, the new chips reserve less than a full die for redundancy (so-called "fractional RAISE").

http://www.anandtech.com/show/7520/lsi-announces-sandforce-sf3700-sata-and-pcie-in-one-silicon