Product:
Cognos Controller 10.1.1
Windows 2008 R2 server

Symptom:
Limit memory on Cognos Controller server, how do I tune Cognos Controller system to use less RAM ?

Possible Solution:
The Cognos Controller standard reports use the old CQM report engine, so you can turn off the new DQM report engine in the new Cognos BI that is shipped with Cognos Controller.
This will save you one JAVA session.

Go to Cognos Configuration on your Controller Application server.
Go to Environment
Go to IBM Cognos services
Under Component Properties – set “Query Service Enabled?” to false.
Save settings and restart the Cognos BI services.

In windows task manager you should now only see one JAVA.EXE*32 process instead of two that you had before.
Will save around 343 Mb of RAM from the Controller application server.