Best Software setup for CS5

I just built an X79 box, 3930K, Rampage IV Extreme.

The MOBO has:
2 ASMedia ports, 1 being using for an optical drive
2 Sata 6GBS Ports, 1 has the OS/Programs on an SSD, the other has my 3TB data drive.
4 Sata 3Gps ports -- This is where my RAID0 is.

Right now, I have 3 drives in a Raid0 with windows disk management, getting sustained transfer rates ~400MBS. This array is solely used for Black Magic Intensity Capture.

Question is, do I add the 4th drive to the array (which will give me ~550 MBS xfer) and use it for both Capture and a Scratch Disk, or should I let the 4th drive live on it's own (outside the array, ~160MBS read/write) as a separate scratch disk?

I am not concerned about data in the RAID0. Once it is captured, it is backed up to both my data drive and an external QNAP NAS.

PS -- I don't do video for a living. It's just my own recordings used for corporate training/marketing. Call me a hobbyist I guess.