This is a LINK to an article that I posted to the Premiere Elements Tip & Tricks sub-forum. I'm linking to it, because it contains additonal links to two articles by Harm Millard on computer equipment to consider and then I/O setup. I linked to that sub-forum's article, because both article links are in it.
The links come back to the Adobe PrPro CS4 forum, and to Harm's excellent articles.
Before you buy, or build, you might want to consider what Harm has written in both of these. It will be well worth your time to follow the links and to read. Eddie Lotter has also linked to these articles from the PrPro-wiki. That is how good and useful we think these two articles are.