How to evaluate cost/performance gains for the G5?

[MacSpec]

I am new to Macs and am building a spec. for a non-linear edit suite using Apple goodies, but need advice from experienced users.

What are the likely benefits of opting for a twin-processor G5? Is the software (Final Cut Pro, DVD Studio 2), optimised for 64 bit processors?

How much RAM should I install? In this application the usual bottlenecks of Web server speed and disc read/write times are not so much of a problem, but as Gigabyte chunks of RAM are expensive how can I work out the cost per performance gain equation? If I won the lottery I would install 8Gb no problem, but would it be worth it? Is the performance gain with extra RAM linear, or does it drop off once a good chunk of RAM is available?

(I expect to be editing quite long DV footage).

 

[pianojoe]

>You should be fine if you max out the machine using 512 bricks -> gives you 4GB total.

 

[MacSpec]

Dual G5 supposed to take 8Gb in 1Gb chunks, and I am sure that would be fine - but would it be worth the £2200 or so that would cost??