Still if you overclock a 2500k to the MAX and do the same thing with the 3570k you will have more performance then the 2500k.
The sandy bridge gets more % performance boost but still can't quite match the IVY bridge in raw power.
But you need to be a little more aware of the cooling because the IVY bridge tends to get hotter a little faster then sandy bridge.
The RAID0 setup is.... you know what, it would be easier if you just watch the video below.
He is great, and better to explain it then me.
First he is talking about RAID0 and RAID1, then he shows you how to set it up. All you can ask for in a RAID0/1 video is there.