[fny]

The real advantage comes from the fact that JRuby isn't enslaved to a GIL like MRI, so you get JVM threads out of the box. Even with the JIT, JRuby (at least 1.7) isn't appreciably faster than MRI when running a single-threaded app: http://www.isrubyfastyet.com/

[headius]

These benchmarks are very small and do not run long enough for the JIT to really kick in. Many of them are also so synthetic as to be meaningless.

[Freaky]

50,000 requests aren't enough for the JIT to warm up?