LHC@home

Recently theory has been overloading my computer and causing blu screens. I was able to solve this by telling boinc to use 87.5% of my cpus.
However every other project runs fine with 100% cpu usage so I dont want to limit them when Im running them. I saw a post about app configs to limit the maximum number of concurrent tasks. Ive made one that I think is correct and just wanted to verify.

<app_config>
 <app>
  <name>Theory</name>
  <max_concurrent>28</max_concurrent>
 </app>
</app_config>

This should be all I need correct?

Yes that's correct, when you have only Theory selected in your preferences.

Another way would be

<app_config>
 <project_max_concurrent>28</project_max_concurrent>
</app_config>

for all LHC applications together.

So theres no way to only have theory restricted to 28 tasks, and everything else can use 100?
If I just want theory limited to 28 tasks, I have to restrict my preferences to only run theory tasks?

No, you can restrict the number of running Theory's on your machine to 28 with your first app_config.xml.
It will not restrict the number of Theory's loaded from the server. The server is not aware of the use of an app_config.xml.
The rest of the cores can run other applications.