Looks like your Block size is set below your Stripe size. Do like DSee said above, set the block size in HDTune to 512k or larger. You're basically benchmarking a sigle disk in your array right now.
I've got 8 of these drives in a raid array so they never really spin-down, but they are some of the quietest drives I've ever used. I did also have one that was DOA and it had the click o' death sound...That one, you could hear spin up, then a loud click and die, then it would repeat that cycle...