As promised, here are some filesystem benchmarks for Ghostwheel. The tests were hardly scientific, but the results are consistent enough to compare the different types of storage the box is running.
For the sake of comparison, I also tested a 7200RPM IDE drive, which ended up getting better scores than the RAID-5 array of Serial ATA drives. Apparently RAID-5 has a little more overhead than I thought it did. With the exception of the IDE drive, all the drives were connected to a 3Ware 8506-8 RAID controller (the system drive is not in a RAID array, however).