there are different levels of raid, yes it provides data recovery .. on for instance (RAID 1) .. i think this is a one-one mirroring of one HD to another. if you have a hardware raid then there should be no decrease in access times and no overhead if its software raid .. through windows then you will encounter at least some cpu overhead... however if you have some sort of STRIPING in your RAID, for instance RAID 5 ?.. you would need a min 3 HD's for this . then you should get an INCREASE in HD performance (if its hardware type raid) and also one disk is used for redundancy (error correction). So :) in conclusion IMHO if you have hardware RAID 5, or RAID 0 (striping no parity I think), then you should keep your Paging file on the RAID disk.