Just from my DSS Lite test with my 3Ware I get higher when enabling the cache.

hdparm -t /dev/sda
*-----------------------------------------------------------------------------*
/dev/sda:
Timing buffered disk reads: 354 MB in 3.00 seconds = 117.99 MB/sec

Also are these ES (Server ) drives. Try direct connecting to the server. You might want to force the speed to 1000 instead f auto neg in the modify driver feature in the Console Tools.