Matthias, yeah I'm not going to use it for the swap file. I've seen benches on ram based swap-files, and it turned out you were just as well off putting more ram in rather than going through the trouble of making a RAM-Drive.
I plan on RAID 0'ing 4 of them, and putting BF2(the game) on there, maybe the OS minus the swap file as well. I'm steering away from USB because it's limited to 66MB/s and I doubt that's per port, I'm fairly sure that's across the whole bus, unlike SATA, where the bandwith is per link.