Scratch disk - RAID partition ??

[osprey]

I have a new PC with 2 x 235 GB discs configured as RAID 0 (stripe)
All works Ok.
I use Adobe Photoshop CS3 and for optimum performance requires a scratch disk that should be:

#On a different drive than any large files you are editing.
#Scratch disks should be on a different drive than the one used for virtual memory.
#Scratch disks should be conventional (non-removable) media.
#Raid disks/disk arrays are good choices for dedicated scratch disk volumes.


I don’t have a physically separate drive … can you create partitions on RAID 0 set up ? …. And would it give the necessary benefits ?
If the answer is yes – how do I do this, and would I lose all current data/OS

Dell advise I can’t add another HDD, other than to use a USB connected one.
Would USB 2.0 be fast enough ?

[Tomi]

Dell chat crap mate. Stick another HDD in it thats what i did. Infact i ripped my dell machine to shreds, only an old HDD and the graphics card which came with it are the remains of dell. I replaced everythin else