Raid 10 is 4 or more drives. Raid 10 is two sets of raid 1 drives connected logicaly with a raid 0 stripe.
You better off with Raid 10 (if you can spare a drive), its alot less work for the cpu. also you can loose 2 drives (depending on what drive it is) if raid raid 5 loses a drive the array will slow down ALOT, and a second failure will killthe array.
Raid 5 on 3 drives is very slow compared to 5 drives. Raid 10 on 4 drives is REALLY fast.
My raid 5 array (across 5 disks) was slower (173MB) then my Raid 10 array (across 4 disks) (197mb)