yeah Jerry's right on. The Processor speed, RAM and hard drive setup will be the most determining factor. Also your workflow- whether you are planning to edit proxies, Log and Transfer .R3D or ProRes or downconvert to something else.
- For HDTV get a Kona card and decent monitor – a computer display won't show your final color and contrast.
- Transcoding with REDrushes or Clipfinder is much faster with more RAM.
- Color doesn't work with more than one graphics card.
Hope this helps,
Director of the Institute of Media Research (IMF) at Braunschweig University of Arts