We just provisioned a new server with Sandy Bridge and 4 SSDs in RAID 5 configuration. The server it was replacing was seriously under powered so this is a timely replacement. I ran hdparm on both servers to compare:
Old Server:
dag:/home# hdparm -Tt /dev/sda6
/dev/sda6:
Timing cached reads: 6678 MB in 2.00 seconds = 3341.64 MB/sec
Timing buffered disk reads: 186 MB in 3.03 seconds = 61.38 MB/sec
New Server:
root@dagnew:/home# hdparm -Tt /dev/sda6
/dev/sda6:
Timing cached reads: 25048 MB in 2.00 seconds = 12539.88 MB/sec
Timing buffered disk reads: 1956 MB in 3.00 seconds = 651.75 MB/sec
I'll be rolling out more of these when other servers are up for replacement.