How Fast a Drive Is Needed for Optimal Photoshop File-Save Speed?

How fast should the volume speed be to maximize Photoshop CS5 save speed assuming one is using the DisallowFlateCompressedPSD.plugin?

My report discusses the issue for 1/2/3/4 drives.

Note that by default, all MPG Pro Workstations ship with a 2-drive RAID-0 stripe, which yields a big chunk of the improvement. For working with really big files, a 3 or 4 drive stripe is possible, but that also requires external Time Machine storage or similar protection. I personally use a 3-drive stripe for my main machine, along with an external Time Machine backup (and many other external backups).

Time to save 2.88GB PSB file with and without the DisallowFlateCompressedPSD.plug

Number of drives (single drive, or RAID-0 of 2/3/4 drives)
Seconds, lower is faster