In answer to Don's question, Penguin Computing recently released the
Altus 1240 (http://penguincomputing.com/) that consists of dual AMD Athlon 1.2 GHz and 3.5 GB of dram. It's in a 1U config and only supports 4 hd, but your DB may be on another box (I haven't studied this thread very well).
Although Penguin is reportedly having a rough time right now (at least that's the rumor on f**kedcompany) we have a couple of their servers and they run like a dream.
talli