Q3Bench is a program that automatically benchmarks Quake3 Arena and Return to Castle Wolfenstein by using customized configuration files and scripts generated from the selections you make. It then starts Quake3 while it exits. When Quake3 is finished running the benchmarks, it will exit and you simply need to launch Q3Bench again to generate the results. It will gather these results from the console dumps Quake3 was instructed to generate. The results will be written into a easily readable and formatted text file. If multiple runs at each setting were selected (as
recommended), averaged results will be computed and added to the report file for you!

From the author:

This has been a complicated project that has taken countless hours to design and validate. We are very excited about this utility because it literally turns hours of work into minutes. This program is 100% freeware, and our only goal was to provide you (the user) with a valuable tool. We hope you enjoy it and find it beneficial.