in reply to architecture width ?

If I have a 64 bit cpu, do I need a 64 bit release of Perl?

No. Leastwise not on Windows or (those varieties of*) *nix I am aware of. The 64-bit versions of will also allow you to build and run 32-bit binaries.

(* there are so many vareties, there might be some that won't; who knows :)

Are there other factors in play?

Other factors that enable or prevent what?

A 32-bit binary will be limited to using 1 or 2 or 3GB of ram per process depending upon your OS and build parameters; regardless of how much is physical available. But the 32-bit Perl will use somewhat less memory for a given size of array or hash, because it only needs 4 bytes per pointer rather than 8.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In Section Seekers of Perl Wisdom