I have 2 new HDs to add to PC - where will they help the most?

Question

I recently purchased 2 new Hard Drives (1TB SAMSUNG F1) that match the ones I currently use in my Intel core i7 PC running Windows 7.  I'm wondering where these new HDs will do me the most good, as far as performance and considering future growth, etc. 90% of my work is in 1080i at about 130Mbps  Oh yeah, I'm on a budget, so thanks for not suggesting I buy 10 more drives and a high end RAID card ;-)  FYI, I'm currently using the motherboard's Intel RAID controller.... I know - I would love to buy a real RAID card!!
Here is my current HD set-up - total of 4 Samsung 1TB F1 7200 RPM:
Drive c: OS and apps
Drive d: 2 disk RAID0 - I set this for "capture" within each PPRO project. I also send media encoder renders here because the sources files are mostly rendered files on the e drive. Plus I often want to back-up these encodes along with the capture files.
Drive e: "render drive"  - target for PPRO preview renders, caches  (including Cineform renders)
* I realize the flaw with above now - since I use the Cineform CODEC for most edits, almost every clip ends up needing to be rendered, so my poor solo render drive is actually doing more work and playing bigger bit-rate files then my capture array. (I may or may not get a capture card at this point)
** the other issue that comes into play here is which files need to be kept and backed up and which drives can be regularly restriped. From my short time with PPRO, it would seem that none of the PPRO preview or cache files need to be saved or backed up....just the capture files and any media encoder files that I want to keep.  Am I missing anything here?
So, I see my options as:
add both new HDs to render array to create a 3 disk RAID0 for renders/previews, leaving the 2 disk RAID0 for captures
add (1) HD to render to create a 2 disk RAID0 render array and use the second new HD somehow to improve performance or workflow
Thanks for your advice on how best to use the two new HDs to improve my system. I think that I only have 6 SATA plugs on my motherboard (ASUS P6T V2), so this fills out my internal HD options.
Thanks!
           Jim

Answer 1

Baz,
Thanks for your helpful post!  I am trudging through an upgrade to Windows 7 retail from the RC. It worked but is not very stable, so I may have to do a clean install.
Anyway - since you just went through setting up a RAID5 using the Intel MoBo feature, I was hoping that you would be willing to reply with a basic "How-to" or list of steps involved.  It has been 8 months since I played with the hard drive arrangement and I can't remember what I did or how, ie, do I start with doing things in the BIOS, how do I stripe the RAID5, etc.  Any help would be appreciated!  In the meantime, I'll download the Intel Matrix software as you suggested.
Thanks,
              Jim
My current arrangement is below. I have two new Samsung F1 HDs to add to these. FYI, the new drives are the same make/size as the existing, but are the commmercial grade. The existing HDs are the ordinary grade....I assume that these will work together in a RAID5 OK.
MoBo = ASUS P6T Delux V2
CPU = Core i7
Disk 0 = OS, boot, page file, primary partition
Disk 1 = video files  (capture)  *  this is a RAID0 using two 1TB Samsung F1
Disk 2 = renders  * single 1TB Samsung F1