As JDeveloper is built on top of Java graphics libraries, there will always be a lag in the design view for two reasons:
1. Java graphics rendering, which is slower than native windowing toolkits in general.
2. JDeveloper is interpreting your JSP into a graphically-viewable window.
With both issues, "more CPU and more RAM" will help in general, but I don't have benchmarking statistics about the performance of JDeveloper with either. I will say that JDeveloper 11gR2 is much improved performance-wise over JDevloper 11gR1 and the 10g releases, and I do look forward to being able to do FMW development with the newsier versions!
My own machine specs are also governed more by the operation of Fusion Middleware than JDeveloper itself - so my own specs (MacBook Pro dual core i7, 16GB of RAM) are based around the need to run multiple WebLogic managed servers for FWM installations and/or Virtual Machines.
We'll be having a guest from the JDeveloper IDE team itself - be sure to raise your question (or hopefully she'll see this note as well) then…
- Chad