PTC plans to ship the 64-bit version of its Pro/ENGINEER Wildfire 2.0 CAD software on the same day that Microsoft releasses Windows XP Professional x64 Edition. It'll run on IBM IntelliStation A Pro computers that use AMD's Opteron CPU [burn to Intel!].
PTC says that a 64-bit CAD system "reduces the memory limitations of 32-bit-operating systems that forced users to divide large datasets to conform to the memory restriction, allowing access to an unimaginable 18 billion GB of addressable memory."
Emphasis on "unimaginable."
What this means is that CAD software is no longer limited to accessing 2GB RAM (in Windows 2000) or 3GB (in XP). In practice, Pro/E is limited to accessing the amount of memory in the computer, and for now that's not going to be 18TB. [Gosh, and to think that at one time Microsoft thought that 0.64MB was more than enough for anyone's needs.]