I figured something out. Running something like:
# time zip -r test.zip some-very-large-dir/
shows the real, user and sys time. The optimized kernel shows an improvement of 0% to 2%...a complete waste of time! There goes Gentoo down the drain
(don't get touchy)
I will try a more scientific approach with proper mathematic correction for the results, but this unscientific starting point shows little promise.