Seems more appropriate here than at StackOverflow; we'll see if it gets closed.
Let's say I have an IIS App Pool set to cap at 25%. But the pool runs a webservice which spawns a process. Is that subsequent process subject to a subset of that 25% or does it get full reign of the CPU? And if so, how can I regulate it to stay within the set limit?
If it's a full-blown new process, there's no way you can control its CPU allocation; a new thread in the same process would instead be costrained by the same limitations of the process that spawns it.