Installation of each Ruby version and Mail gem was really easy so I will not describe it here. What interested me was how fast was Mail on each Ruby implementation.
I have created a simple mail and saved it as 1.eml.
This script will read the file, display subject and time elapsed (in seconds).
I have executed the script three times for each Ruby implementation. It looks to me that CRuby and JRuby are similar in speed, and IronRuby is way slower.
Tests were run in VMware Fusion 2.0.6 virtual machine, 512 MB RAM, Microsoft Windows Sever 2003 R2 (Standard Edition, Service pack 2).
Host machine is MacBook Pro, 2.4 GHz Intel Core 2 Duo, Mac OS X 10.6.2, 4 GB RAM.