Sun recommended JVM Settings

GC Settings
   -XX:+UseConcMarkSweepGC
   -XX:+CMSIncrementalMode
   -XX:+CMSIncrementalPacing
   -XX:CMSIncrementalDutyCycleMin=0
   -XX:+CMSIncrementalDutyCycle=10
   -XX:+UseParNewGC
   -XX:+CMSPermGenSweepingEnabled
To analyze what is going on
   -XX:+PrintGCDetails
   -XX:+PrintGCTimeStamps
   -XX:-TraceClassUnloading
                                   
Minor Notes
-XX:+UseParallelGC <> -XX:+UseParNewGC
-XX:ParallelGCThreads=
    Use with ParallelGC setting
If you have 4 cpus and 1 JVM
    Set value to 4
If you have 4 cpus and 2 JVM
    Set value to 2
If you have 4 cpus and 6 JVM
    Set value to 2

INSIDE THE JAVA VIRTUAL MACHINE / Filip Hanik