Windows XP and RAID-0 performance questions

I have a couple of noobish questions about XP and RAID-0. I 've been told that XP installed on a RAID-0 array runs slower than XP on a non-RAID hard drive. Is that really the case?

In my case that prompted me to install XP pro on a non-raid boot drive, but I put windows swap file on the RAID-0 array in my rig. Will that improve xp performance? Is there a way to check this with a windows benchmarking tool?

Thanks