to do this kindof thing- cheaply- you need to be aware of the quite large differences in performance between different hard discs - nothing to do with catalyst or any other software.

it is a combination of the interface type and hard disc choice that makes this work.
you need a fast interface - and fast hard discs.
And to get anywhere the bandwidth required - you will need at least 4 discs - all working well together.
if you get either one wrong - it wont work well.

this is an article about the speeds of different large sata drives:

http://www.barefeats.com/hard68.html

www.storagereview.com
gives the basic stats for almost every drive