in reply to Out-Of-Date Optimizations? New Idioms? RAM vs. CPU
I am reminded of the original development of RISC machines. Those guys found that the only way to find the "best" approach was to take a sufficiently large example set (booting UNIX and running some programs) and run it in a well measured simulation. When someone proposed a change to the architecture they changed the simulation, measured the effect on performance and kept it if it improved the situation.
My guess would be (based admittedly on a total lack of first hand knowledge) that adding metrics to Parrot (or Perl 5?) that emulated the effect of fetching information from disk/ RAM/ cache would lead to a reasonable simulation of Perl's performace and hence could definitively answer these type of questions.
This would allow anyone with enough interest and time on their hands to get a real answer rather than just sticking a wet finger in the air.