Phoronix: Ubuntu 11.04: i686 vs. i686 PAE vs. x86_64

At the end of 2009 I published benchmarks comparing Ubuntu's 32-bit, 32-bit PAE, and 64-bit Linux kernels. Those tests were carried out to show the performance impact of using 32-bit with PAE (Physical Address Extension) support, which on the plus side allows up to 64GB of system memory to be addressable from 32-bit machines, but is still significantly slower than a 64-bit kernel and user-space. In this article the tests have been carried out on modern hardware and with the latest Ubuntu 11.04 packages to see how the three kernel variants are performing in 2011.

http://www.phoronix.com/vr.php?view=15873