HP Smart Array E200i performance

I have at home a pretty nice server: HP ML350 G5. My model has one Quad-Core Intel Xeon Processor X5355 (2.66 GHz), 8 GB of RAM and 4x 250 GB SATA II, 2.5'', 5.4k disk drives.

I have this HW for over three years now, but never really tried to do anything besides installing an operating system and grinding some boxes. Recently I decided to run some quick tests to see the actual performance of the disks.