You can chart the Process: Thread Count: Inetinfo value over time to see how many threads the Inetinfo process creates and how the numbers of threads vary. Then, observe the processor time for each thread in the process (Thread: % Processor Time: Inetinfo => Thread #) during periods of high, medium, and low server activity (as indicated by the other performance measures).
You should also observe the patterns of context switches over time. Context switches indicate that the microkernel has switched the processor from one thread to another. A context switch occurs each time a new thread runs, and each time one thread takes over from another. A large number of threads is likely to increase the number of context switches. Context switches allow multiple threads to share the processor, but they also interrupt the processor and might interfere with processor performance, especially on multiprocessor computers.