Thinking about it the threads in a game that normally need more CPU time are the ones that are doing lots of sys calls. You'd have to use a fair bit of async and atomics, to split the work into compute and chatting with the kernal. Might as well figure out how to do it 'right' and use 2+ threads so it can scale. Side note the compute heavy low sys call freqency stuff like terrain gen belongs in the pool of back ground threads, normaly.