Anandtech actually has an article explaining SSD caching tech. Basically what it boils down to is this: SSD caching, actually called Intel Smart Response Technology or SRT, supports up to a 64GB cache on a SSD. What that means is if you have a large capacity HDD, you can purchase a much smaller SSD and use SRT to cache your common applications to the SSD for a moderate increase in responsiveness. Basically its meant for people who want both large capacity storage and a little SSD speed, without having to pay upwards of $200 to keep everything on one SSD.