Ubuntu 11.04: i686 vs. i686 PAE vs. x86_64
Written by Michael Larabel in Operating Systems on 4 April 2011. Page 7 of 9. 43 Comments

POV-Ray, which is a single threaded test, had regressed when using the 64-bit Linux environment. The 32-bit PAE performance was indifferent to a non-PAE kernel.

Smallpt, another multi-threaded test, heavily favored 64-bit computing.

FLAC audio encoding was significantly faster in a 64-bit environment.