Best Raid 0 for PS CS3 and Mac Pro

Question

I am getting closer to ordering a new Mac Pro to run PS CS3 - and to drive 3 big Epson printers. I am leaning toward the dual-core 3.0 GHz as the results and speed for the 8 core with PS CS3 are still not known. It will have 6 to 8 GB of RAM (depends on my budget).
I want to make a machine that will do only PS CS3 - at the fastest possible rate. I have lots of other Macs for running other applications. I plan to order the Mac Pro with 1x 500MB hard drive - and add 2 smaller, but faster drives for the OS and for PS - and for the PS scratch/cache- and to put that on a Raid 0.
I am looking at getting 2 Raptor 150MB 10,000 RPM drives for the Raid 0. They can be small -maybe even just the 70MB versions -as I would only use them for booting OS and for running PS CS3. Images would be saved to a different disk. I have 10 external LaCie FW800 drives for image storage and backups. I will also use the 500MB drive that comes with the new Mac Pro for image storage - and maybe add a 4th similar 500 or 750MB drive for additional storage on the mac Pro itself.
My thought is that if I only have the OS and the PS on the Raid 0 a total failure would do little harm. I would not lose anything except maybe the image being worked on at the time of failure. The applications and OS could be rebuilt from the install CDs.
Is this a good plan? Is there another way to get maximum PS CS3 speed on the new Mac Pro?
Dual 2.7 G5, 2 intel iMacs, 1 MacBook, 1 Powerbook, 18 G4 Macs, 3 iPods   Mac OS X (10.4.9)   I teach Digital Photography clases - on Macs

Answer 1

Some considerations:
Ideally you want to use separate drives (or RAID volumes) for:
1. Mac OS X and Photoshop
2. Scratch space
3. Storage of images that you're processing
If you use a striped volume for the boot disk, then you'll have to keep another bootable disk to perform some firmware updates (firewire drives work well) - you'll want to do this anyway with a RAID 0...
Buy your RAM so that you can get the quad-channel performance...
If you are comfortable working inside the computer, you can also add a 5th/6th drive in the optical bay. To add one extra drive, you just need 5.25 drive mounting bracket. For two extra drives (or even 4) you can use this product:
http://www.maxupgrades.com/istore/index.cfm?fuseaction=product.display&product_i d=158
I found that an 18" SATA cable with elbow connectors is the best... you'll also want a 6" SATA power adapter (4pin-15pin)
My suggestion would be to add a 5th hard drive to the Mac Pro. That way, you could use (1) 150 GB raptor as the boot/PS disk, and then created TWO striped RAIDs with the 4 remaining disks. Perhaps (2) raptors for a scratch stripe, and (2) disks for users/storage. If your storage needs are less than 300 GB, then get 5 raptors...
If your LF Epson printers are firewire, then you'll want each to be on it's own firewire bus - get additional PCIe firewire cards as needed.
All of the drive recommendations above assume that you're doing daily (or more often) backups of any RAID 0 stripes that you create...
EDIT:
On second thought, you might want to stripe the boot drive for better printing performance (waiting for OS to write to the spool)... so perhaps add a 6th internal SATA disk and have 3 unique 300 GB (striped) volumes.