I have some 32-bit Win2K3 servers running an application that fails now and then apparently due to heap fragmentation. (Process virtual bytes grows, private bytes does not) I do not have access to the source code or build process of this application.

I have modified the boot.ini file on one of these servers to include /userva=2560, half way between the normal mode of operation and the /3GB option. Normally it takes weeks to reach the point of failure, but I'd like to see right away whether this has actually had any effect.

As I understand it, this option limits the kernel to the remaining address space (1536MB instead of 2048), but does not necessarily give an application the extra address space, depending on the flags in the application's PE header.

How can I determine whether the O/S is allowing a particular application, running in production, to access address space above 2GB? Additionally, what's the best way to monitor the system to ensure that the kernel is not starved for address space, and more generally how should I go about finding the optimal value for this setting?