So maybe I'm misunderstanding something here, but running a lot of idle things at slightly >0% is doable on a single core. my quadcore machine doesn't start sho

So maybe I'm misunderstanding something here, but running a lot of idle things at slightly >0% is doable on a single core. my quadcore machine doesn't start showing hickups until the load is up to 12, implying I can run 3 fairly heavy tasks per core before it starts being a problem, I'd imagine I could run a lot more low-cpu tasks per core than that. So why do you need a lot of cores for multitasking like that again?