I have two virtualized instances of Windows Server 2008 running IIS. Each machine has been given 8 GB of RAM, and while they are only running a few clients with a few applications each, memory usage was running at 75%. This doesn't include swap file usage; just pure raw memory.

There is some kind of memory leak, I suspect. A restart of the system brought it back down to 14%.

24 hours later, memory usage at 22%. I'll keep an eye on this.