for comparison purposes here is my Mac's Spec
Model Name: Mac Pro
Model Identifier: MacPro1,1
Processor Name: Dual-Core Intel Xeon
Processor Speed: 2.66 GHz
Number Of Processors: 2
Total Number Of Cores: 4
L2 Cache (per processor): 4 MB
Memory: 9 GB
Bus Speed: 1.33 GHz
I have both CS3 and CS4 installed and both are memory hogs, in my experience you cannot have to much memory when running DW and especially when running large complicated extensions like DataAssist. Running the DataAssist wizard in CS4 took approx 21 seconds to run from pressing the finish button.
What I have done is to create a series of pages (these contain validation and other code I use regularly) that I use as templates rather than running the wizard each time I need to create a set of admin pages.