>Invite a tech rep from the vendor by to see if it is normal.

That, we have covered now, since we had the initial ML530 test box the LAN HW guy used to approve the model to compare with. It sounds the same, except it's located in a LAN server dungeon where the noise is not a big issue. So I'm pretty sure the noise is standard, it's just that the LAN HW-tester did not consider where most of these servers will be located.