It depends on how many policies, and which type of policies you register. In general, each EEM event detector process holds around 10 KB of RAM at any given time with the server fluctuating depending on what policies are registered and executing. As for CPU resources, it again varies depending on what you are doing with EEM.
Currently, EEM can be found in various versions in 12.2(25)S and higher, 12.3(4)T and higher, 12.0(26)S and higher, and 12.2(18)SXF5 and higher. This means that the GSR will have EEM 1.0 provided it's running 12.0(26)S or higher, and the 7609 will have EEM 2.1.5 provided it's running 12.2(18)SXF5 or higher.
See http://www.cisco.com/en/US/products/ps6441/products_configuration_guide_chapter09186a00807c676c.html for more information on EEM, and what capabilities each version has.
