Silicone Image Raid Controller
I will say that RayIt is correct in that Ubuntu does not seem to recognize a raid setup with this controller. It has no problems detecting the two drives and utilizing its SATA driver to access them. I setup a raid 1 set (striping) prior to booting from the install cd. It booted then during the partitioning gparted didn't see it as 1 drive it saw the two individual drives. So I don't believe that Ubuntu 6.06 (don't know about other distributions) works with this raid controller.
I exited the install, removed the raid1 set, then installed and partitioned with two individual drives. I don't think that I will notice the performance difference between the two drives and the raid set.