The following KB article describes how to create a second application pool and mentions that the SD.Feeder Projects can be placed to be run in there: http://www.symantec.com/docs/TECH122138
Having implemented the above suggestions and looking at the CPU utilization of the SD7 (on a 16 core machine) I an clearly see that only one core is mainly utilized while the other cores do not do too much work. The new application pool will utilize another core, whenever a user or worker opens a form, but the main work of console navigation and background processing is still handled by a single core through the default app pool.
In a test environment I have now successfully created yet another application pool and moved the "ProcessManager" website under it, seeing much better CPU utilization (3 cores now for SD alone).
Anyway I'd like to know, if anybody is using a similar setup in production as well without any issues. I would be ready to create even more application pools, as we have 30 GB RAM and 16 cores, but the system is not really utilizing those properly.
Any feedback of other installations with multiple application pools would be appreciated, including which website you've moved to different pools.