What's this got to do with triple channel memory?
Anyway, hard disks in RAID 0 means that the disks are striped. Basically, both of them are used to split your data to improve speed at the expense of reliability; if one drive goes, your data is unrecoverable on both drives.
Are you making a mistake? Personally, I don't use RAID arrays at all. I like being able to hot-swap disks between numbers of machines - RAID doesn't allow me to do so. If you don't have data that you'd like to keep for extended periods (pictures, movies, memories) I wouldn't trust RAID 0 to hold them, especially on notebook drives which are more prone to failure. Otherwise, RAID is an excellent option to improve performance (at the expense of battery life, of course, but with a 280 that will already be non-existent).