Coming up in our forums was a testing request to compare the
performance of Linux between using 32-bit, 32-bit PAE, and 64-bit
kernels. This is coming after Linus Torvalds has spoke of 25%
performance differences between kernels using CONFIG_HIGHMEM4G and those
without this option that allows 32-bit builds to address up to 4GB of
physical RAM on a system. We decided to compare the performance of the
32-bit, 32-bit PAE, and 64-bit kernels on a modern desktop system and
here are the results. Read more at Phoronix.