If you've read my past posts on here, you'll probably find a trend: I'm obsessed with performance tuning. Any time you can get more responsiveness without more hardware, I'm very, very happy. I've been running a modified drupal core for ELMSLN for some time now and decided instead of keeping these changes / tuning to myself, I'd try and document them / test them and see if any changes make sense for pressflow.
you can see 3 folders:
_PATCHES - all the patches (from drupal.org) utilized in the metrics
_RECIPES - a drush recipe that auto optimizes to the level used in testing, there are also recipes for each of the sites in the test so you can see exactly what was used for testing.
_METRICS - XLS file with detailed metrics of how testing was performed, where, and what combinations