Well, to not answer your question: Hotspot performance tuning is a fine art, and benchmarking is a somewhat separate fine art, people will sample their data carefully, do a lot fo runs, warming up properly, using different GC's, tuning heap,GC generations, MaxInlineSize, maybe 32-bit (-server). I remember reading linux package managers often don't include -client in the 64-bit install. JDK7 maybe faster, many people have said no difference between sun/Oracle and openJDK (except launcher and fonts, for IDEA, you must have sunjdk), and in some cases JRockit performs more predictably.

Here's some blogs that i like about this:

http://openjdk.java.net/groups/hotspot/docs/RuntimeOverview....

http://q-redux.blogspot.com/search/label/all%20jvm%20options

http://redstack.wordpress.com/2010/12/09/recommended-jvm-par...

http://marxsoftware.blogspot.com/2011/10/javaone-2011-defini...

http://blog.headius.com/2009/01/my-favorite-hotspot-jvm-flag...

http://groups.google.com/group/jvm-languages/browse_thread/t...

http://stackoverflow.com/questions/tagged/java+hotspot?sort=...