It depends what you mean by performance?
No! two hard drives are NOT quicker than one! if that is what you mean?
If you have to use more than one drive YES it is better that they are matched but not essential.
But if all you are talking about is speed then just buy one large drive.
IDE, go for one of the latest 7,200rpm Maxtors or IBM GPX 120 drives. Martin Please let members know if there advice has helped any.