I have a 8-core MP 2.8Ghz with 10gb ram and Ati 2600HD. I'll someday replace the ATI with a quadro (all my application is 3d/CAD/Design) I'm installing 4 of the WD640 drives, they arrive on Friday. I would love to order the CalDigit RAID card but after searching I finally figured out it's not available until next month. That said, I need my system to start working ASAP and I don't want to wait if I don't have to. I'm a designer, I need fast scratch so some striping needs to be involved. I also need data protection. At this capacity Time Machine isn't going to be of any use and I'd prefer redundancy anyway. The 4 WD640s are replacing: 1 750gb 7200.11, 2 WD SE16 500GBs, and 1 320GB (Apple Stock Drive). I would like to sell some of those drives to defray the cost of this endeavor but I'm open to keeping 1 or possibly 2 as external drives or stuffing one into the optical bay with a converter. I want speed and reliability, of course! But really the largest motivator here is the combined drive aspect. Having so many volumes is driving me nuts. My intention had been RAID 5 or 6 but I now know that Apple Software RAID can't do this. So now it seems with software RAID 0+1 would be the only option. Realistically, does the cpu performance degradation outweight the speed gained from striping the drives? It's so difficult to determine bottlenecks. Any thoughts on my best bet without/before the RAID card arrives. Can I migrate the array after installing the card without data loss? If I just JBOD the drives can the concatenated set be broken up ever? I was thinking I could JBOD until the card came.