Unwilling to leave well enough alone, I ditched the single disk ubuntu install and decided to pull out the big guns: a 6 disk raid 10 install. See the benchmarks below. Not bad for 6 year old SATA drives! Unfortunately the temperatures they're running at (53C) have me a little worried. I'll likely migrate them to some HDD enclosures I have laying around.

750 GB RAID 10 Array 750 GB RAID 10 Array Benchmark 250 GB Hard Disk ATA HDS722525VLSA80 Benchmark
6-drive Raid 10 Single Drive