I have ten 1tb RE4 WD's in a raid 10 (~4.5 tb usable). Using a sata DOM for open-e OS. Seems a waste to use 2 drive slots just for the OS. I am using the 9260 LSI controller as well. I do have CacheCade 2.0, but I don't think that makes any difference because I was getting decent times with that that same test string even before I added the Cachecade. Cachecade really helps in speeding up all the websites so they are snappy and respond quickly.