There are several ruby performance patches, like the falcon patches, that may improve the performace of your application.
I use rvm and was pleased to learn that rvm supports compiling ruby with several of these performance patches. Using rvm with the railsexpress patch, I saw a 20% reduction in the time required to run the test suite for a large rails project.
Here is how you can install ruby with the railexpress patch using rvm.
First make sure you have the latest version of rvm.
Next install ruby 1.9.3 with the railsexpress patch. At this step rvm may have dependencies that require installation.
The railsexpress patch contains the following patches.