Hardware recommendations for editing Avchd and rendering to H.264


We are going to edit Avchd videos and want export them to several Internet platforms -- using H.264 in most cases. The length of the films is from 3 up to 15 minutes. We prefer linux Operating systems.

What are your hardware recommendations? Her are some thoughts -- please comment whatever is your own experience.

1. Processor
... seems to me to be most important. What is better?
a) Intel
b) Amd
c) does it make sense to buy processors with less cores but more threads, or does physical cores outperform processors with more threads?

2. Graphic Card
We are not going to play games or use 3d effects.
a) could a graphic card increase the rendering speed? (Which card are good supported under linux?)
b) are Intel-On-board solutions as bad as some people say?

3. Disks:
a) I'm usually configuring raid0. Seems fast enough. Or is it better to configure work-flow with different hard disks?

4. Linus-Versions/desktops
a) I'm not very satisfied with recent ubuntu, since unity is creating a much higher load without launching any programs. So I switched to Mint with cinnamon. What distro would you prefer?
b) Is a KDE faster?

Thx for replays!

I edit on 64bit Ubuntu on an old 64bit Sempron and 2GB RAM with 'Classic' Gnome, hate Unity, KDE Desktop sucks resources compared to Gnome, fact, horrid.

Encoding and sometime editing done on a dual Xeon again 64bit Ubuntu. Basic NVidia GPU's as kdenlive and MLT are not GPU assisted for effects and encoding. Although I think MLT has some GLSL effects but don't kdenlive exposes them?

Source is generally Canon DSLR h264AVC, proxies are a must whatever hardware unless transcoding to some intermediate, prores, DNxHD etc.

Not sure if RAID will help much for editing, although I have a 4TB RAID its for archiving and backup, copy files to dedicated local non system drive for edit time.

Not sure if that helps much, probably better just installing it and deciding for yourselves if it fits your needs.