Workflow and playback for Uncompressed 10-bit is choppy on my Mac Pro.

I'm preparing to work on an Uncompressed 10-bit footage that was encoded from digibeta. I ran a test on my Mac Pro and saw that the playback for Uncompressed 10-bit was very choppy in both FCP and QuickTime. I'm assuming because my Mac Pro isn't installed with a Fibre Channel or an internal RAID hardware so workflow on 10-bit uncompressed will be challenging -- mainly because because of the data rate issue. Even though I have some ideas, I'd like to check with members of CreativeCOW to be safe.

I have two important question and I would REALLY appreciate any answer:

1) What exactly do I need to upgrade on my Mac Pro in order to handle Uncompressed 10-bit workflow via FCP? I have a 2 x 2.66 GHz Dual-Core Intel Xeon processor with a memory of 6 GB 667 MHZ DDR2 FB-DIMM and a NVIDIA GeForce 7300 GT card. It doesn't come with a Fibre Channel or a Hardware RAID device or any Apple Internal Memory Card reader.


2) Would converting digibeta to Pro Res 422 from digibeta instead of Uncompressed 10-bit be a better option quality-wise?

Let me know if you need any more information. Thanks