TurboSnortRules.org is a project supported by security vendor VigilantMinds. The idea is to submit a custom rule to see how it stacks up against other Snort rules in terms of “Relative Measure of Efficiency” The important port is to notice how a rule like this BACKDOOR WinCrash 1.0 Server Active is considered “very slow” (probably due to PCRE matches) compared to something like (IPS) ::MS-SQL Worm propagation attempt, with a RME around 1.4 on Snort 2.2.0.”]
Source: https://taosecurity.blogspot.com/2005/06/test-your-snort-rules-at.html