If your lookin for pure speed you might consider gigabytes i-ram "solid state" HDD. I know its only capable of reaching 4 gigs but it pretty much destroys any SCSI or SATA RAID setup. Just a thought .
here is the better idea:
get several of those with rev 1.3 (so they fit 3.3V PCI/PCI-X or 5V PCI slots, but still I wonder why not a molex connector :roll: if they actually do you'll be able to fit it in a big drive enclosure or something), and raid 0 them (to get more than 4GB, but given they use 2 slots heights each,... you got riser cards to fit 4 of these?) to see what REAL performance are
and I remember somewhere Samsung have flash type Solid state HDD's (for laptop anyways; people say these things will decrease boot time, not sure if that's related to performance) in case you find the idea of a battery not amusing