SRBroker and SRProc in a gist

Server Request Broker (SRBroker)

1.Used to start synchronous Siebel Server tasks
2.Server Request Broker & Server Manager are the only components which directly start tasks.
3.Introduced in in Siebel 7
4.Background component
5.Multi-threaded component
6.Need to set MaxTasks as per the needs.

Server Request Processor (SRProc)

1.Used to start asynchronous Siebel Server tasks
2.Manages queued requests
3.Calls SRBroker to manage task execution
4.Background component

This is a high level explanation which would be very helpful when you sit next time to debug logs;cheers