If you're not using Bundler and have a simple dependency chain, you can get further improvement from symlinking your gems into a single directory (see https://gist.github.com/975509 ).

This patch certainly improved my load time tremendously, but the core of the problem still lies with the way rubygems and bundler dump all directories of gems in the load path. The promise of $LOAD_PATH is that all the directories in it will be tried -- the most bang-for-buck optimization is thus minimizing its size.