[stcredzero]

Is there any reason why you do update() in parallel?

I wanted to come up with an architecture that could support an arbitrarily large world given enough resources. Up to a certain density (from 150 to 250 users per "subgrid") I was close to succeeding.

Afaik a game loop's update() is not the intense part in the game loop but rather render() and IO()

"Render" in the context of a server like this is the IO. One thing you should know, is that this game supported Conway's Life cellular automata at 12 frames/second, completely shared and multiplayer.