I'm not talking about USB sticks.. I'm talking about creating a RAM drive partition from your DDR2 memory, and your OS "sees" this RAM drive as a physical drive like any other hard drive. Don't even try to compare performance - a RAM disk is much faster in every way than any physical disks - SCSI, SATA, SDD, in any config - RAID0, RAID1, etc.

Here's current software to create this RAM disk in Vista64:
http://www.farstone.com/software/virtual-hard-drive.htm

I did it a few years ago using RAM Drive Pro XP to load Diablo 2 data and Counterstrike maps on the drive, and the load performance was incredibly better than my RAID0 36GB Raptors at the time.

The only downside that I can see, aside from the loss in available RAM.. is you'll need to rebuild this drive every time you reboot your machine.