On the basis that the sooner we close this one off, the sooner zippy will think of his next question, may I ask zippy:

1) Is it my processor? What processor do you have?

2) Not enough RAM? How much RAM have you got?

3) Could it be my video card? What video card are you using?

I reckon that if we get logical answers to these 3 questions, then zippy deserves the help of the forum, if we don't get logical answers then he probably needs help from a different direction.

Actually 3) will not make any difference.

To answer the question.

a) Faster CPU will give proportionally better results.
b) More memory may give some improvement but there is an upper limit beyond which you'll get no improvement.

The number of tracks will not have much influence. It's the number of tracks that have to be composited together and the number of effects and transitions.
I know of no way to derive the maths to work out at what limit you go from full frame rate preview to dropping frames, there'd be many factors involved as well in that sort of calc.

farss,

That was a test. The fact that zippy has now moved on to his next question without answering any of these suggests that he is just winding us up!