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.

6-drive Raid 10	Single Drive