RAID1 is about keeping hold of your data (it is simply mirrored on the second drive), if one drive dies you have lost no data. There wouldn't be an increase in speed, more likely a decrease.
RAID0 offers a speed increase by reading/writing the data across two drives.
Read the FAQ.
<A HREF="http://forums.btvillarin.com/index.php?act=ST&f=41&t=2765&st=0#entry21597" target="_new">My Rigs</A>