Exactly this. You want one thread pool of size ~= core count, then you want to have a completely different "max number of IO jobs" type deal that doesn't use th

Exactly this. You want one thread pool of size ~= core count, then you want to have a completely different "max number of IO jobs" type deal that doesn't use threads at all. C# async/await is pretty good for this (IO operations do not count towards CPU task count).