Here's a definition of some RAID levels: http://www.webopedia.com/TERM/R/RAID.html
You can implement level 0 for improved performance but you will need a
controller that supports what you want to do. Try to avoid RAID at the
O/S level - get some hardware that will handle it for you.

Fred,
Yes it is.
There isn't one setup you should choose. You need to juggle the following:
- mirrored pair gives more performance than RAID5
- SQL Log File can be better on its own drive separate from the SQL data,
allowing both to be written at the same time
- OS page file ideally on separate drive, but its a toss up between this and
the SQL log file.
So a typical setup would be either mirrored pair for OS plus RAID5 for data;
or mirrored pair for OS, mirrored pair for SQL logs and RAID5 for data.
Other factors to consider: more memory to save writing to disk; enterprise
editions to use more memory.
Anthony
http://www.airdesk.co.uk