Mac Pro use a lot of RAM?

Question

Does the new Mac Pros Universal Binary Programs use more RAM than the G5 PowerMac?

Answer 1

Overly simplificatiion.
And for many applications, they would still be compiled with 32-bit switch on, they don't need to address 4GB of memory. The GUI is still really not fully 64-bit even.
But code tricks and methods that worked well for the G4 and limited address space, those don't work as well and code is loaded and compiled differently (or should have been). The lack of L3 hurt some too and took a hit in performance and latency making for lack-luster memory performance sub-par from what was expected, and that could be be curied without moving to a new platform or design.
But the MacPro and G5 do probably need about 1.5GB of RAM to run smoothly, which means you have to install 2GB in the MacPro - just for basic use and needs. While waiting for a 2nd GB to ship from Apple my system was constantly using over 900MB from just casual use (web browsing, word processing, email).
I've never been able to figure out how much Rosetta needs, but it seems that it has its own address space and VM all its own.
With CS3 beta running well already, that was something I'm sure Apple wanted as well as all the users holding off - wouldn't surpise me if a lot of help and pressure was put to bear.