Stefan Mileschin

SandForce sets aside more NAND capacity than most controllers for spare area. While Intel, Marvell, Samsung and others default to ~7% of total NAND capacity for spare area, SandForce is almost double that. The difference boils down to RAISE, SandForce's NAND redundancy algorithm that requires the consumption of a full NAND die. The original idea was that RAISE and SandForce's DuraWrite technology could allow SSD vendors to use cheaper, less reliable NAND without any impact to the end user. It seems as though no one was willing to risk using anything but the best NAND, so we never really saw this feature exploited. A bit over a month ago, ADATA released their XPG SX900 series. It utilizes the oh-so-common SF-2281 controller but unlike other SandForce SSDs, RAISE is disabled - giving the end user more usable space.

http://www.anandtech.com/show/5710/t...force-capacity