"Could it be the type of workloads you are throwing at it? We've had 30 VMs under load in production for the last week with great, low pause times without a hint of instability. I'll take a crack at it with your options and see what we see. G1 so far has been useless with full pauses being long and frequent under moderate testing. Ran a 24 hour test last night of JRockit and their deterministic GC with excellent results for our workloads. We also don't use Solaris. It is all RHEL." - Sam Pullara