In a large SCVMM environment we noticed that the SCVMM Service (vmmservice.exe) allocates lots of memory (>4GB). You may notice that you are unable to create new console sessions or existing sessions lose their connection when all available memory is used. This is not a leak as the memory is freed over time.
The reason for this allocations was the large number of jobs that had run in the past. By default SCVMM keeps the last 90 days in the Database and the Console shows this in the Jobs pane. In the title area you can see the number of jobs in brackets. In the customer case we had almost 10.000 jobs.
The problem can be solved by setting a shorter history with the following registry key:
HKLM\Software\Microsoft\Microsoft System Center Virtual Machine Manager Server\settings\sql
DWORD Value: TaskGC
Enter the history length in days. (e.g. 7)
SCVMM starts a maintenance procedure with this number of days every 20h. You may not see a complete reduction immediately, as the maintenance procedure limits itself in the number of objects it deletes in one run. So you may need to monitor this for some days.