Launching Applets using the 64-bit HotSpot JRE are consuming over 600MB of "Memory - Commit Size" (as reported in task manager) in IE on Windows 7.
We have tried setting various combinations of
<PARAM name="java_arguments" value="-d32 -client -Xmx2048k -Xss2048k"/>
but the arguments don't appear to have an impact on the virtual memory reported by Windows.
How can we tune the applets to use less virtual memory?
Other than changing the code to use less virtual memory, no. Virtual memory is just showing you the address space being used by the process, and is not representative of allocated memory. A processes use of virtual memory does not impact other processes.
There is a great answer about why virtual memory use is not concerning linked below. The answer is for Linux but the principles apply to Windows as well.
Virtual Memory Usage from Java under Linux, too much memory used
