How many SAPGUI vusers can I run on each agent?
For all Windows versions other than Windows 2003, Silk Performer can simulate 50 users on a 1GHz/1GB machine. It is not possible to scale virtual users based on machine specifications due to a Windows GDI limitation. GDI is the Graphical Device Interface in Windows. When Silk Performer simulates virtual users every virtual user consumes GDI resources for every control on each SAPGUI screen. Tests show that the GDI limit allows us to run 50 users on a box. In order to run large loadtests additional agents are required rather than more powerful agents.
For Windows 2003 machines testing showed that Silk Performer was able to run 200 users on a powerful machine. This is possible due to Windows 2003 having an enhanced system resource management. As stated previously Silk Performer can simulate 50 users on a 1GHz/1GB machine, therefore it is recommended that you have an equivalent of a 4GHz processor (can be a 4 Way * 1GHZ) and 4GB RAM for running 200 users.