I'm working on a documentary that we have shot with an HVX200 onto p2 cards. We don't have a big budget, but we need to upgrade our system in order to run Final Cut Pro 6, and to be able to handle the HD footage. Right now I'm considering buying a 2.4GHz 20" iMac, and I want to know how well it will be able to handle the HD footage. We will only be editing one project at a time, with little to no effects. I know that the Mac Pro is the most ideal option, but we just don't have the budget for it. Please let me know if this will work for my purposes, or if you can suggest another better and still cost effective alternative.
I have a 24" iMac at home that I edit SD and HDV on, and while not being ideal, it gets the job done. I think the computer will be fine, you main bottleneck is going to be that you are limited to the Firewire 800 bus with no way to add on or expand. Load it up with RAM if you can, this will help as well, as mine only came with 1gb, I certainly feel the slowdown. I think they will handle up to 4 gig, and this will speed things up, especially if you have a large project with tons of clips.
Its more fun to ride a slow motorcycle fast than a fast motorcycle slow...
Matt speaks the truth. I had an editor just do a project for me on a 20" iMac but he did beef up the RAM which helped a ton. The FW 800 is limiting when you have the option of eSATA on the MacPro but it is doable. The intel chip does a decent job of rendering quickly in FCP 6 and Motion.