Why not run the VM with a fixed amount of heap memory? EG: -Xms1500m -Xmx1500m [-server] # fix the heap size at 1.5GB Advantages are: (a) Dynamic heap resizing is avoided thereby avoiding issues to do with object copies, heap fragmentation, generational gc etc (b) Garbage collection is avoided as long as possible. I like to run my VM heap fixed at about 75-85% of primary memory. I would have thought the IO costs to do with logging, perhaps check-pointing, etc would have been significant, perhaps even dominant. Discounting, of course fitness evaluation for "non-trivial" problems. > -- Shane Magrath Doctoral Researcher University of Technology Sydney PH: 61 2 9514 2527 -- UTS CRICOS Provider Code: 00099F DISCLAIMER: This email message and any accompanying attachments may contain confidential information. If you are not the intended recipient, do not read, use, disseminate, distribute or copy this message or attachments. If you have received this message in error, please notify the sender immediately and delete this message. Any views expressed in this message are those of the individual sender, except where the sender expressly, and with authority, states them to be the views the University of Technology, Sydney. Before opening any attachments, please check them for viruses and defects.