I am currently in Manhattan and the weather here is brilliant.  Dan Wilson and myself took lunch today and we chatted about a good number of things; well in reality I was pontificating but that’s another story.  We eventually got talking about High Availability (HA) which is a pet subject of mine along with all things tuning-troubleshooting etc.  We were discussing the dramatic increase in the amount of memory we have available to us in 64 bit environments, as opposed to 32 bit.  Sean Corfield and I did some load testing of 32 bit and 64 bit environments with the same application and the 64 bit was significantly superior in terms of performance.  However, as we will typically want to allocate more memory to the JVM Heap this could create a challenge. 

Dan posed the question as to whether a dramatic increase in the size of the heap would not mean more work for the Garbage Collector in the JVM as there will be more objects to inspect.  I thought about this and in essence I believe he is right.  These are early days for 64 bit although I have already assisted one client with some judicious tuning of the JVM where they had allocated 6GB of Heap Memory. 

Is anyone out there using 64 bit and if so what sort of memory allocation arguments are you passing?