[Mordekay]

Sorry, but i don't get why people try to run a CPU intensive program on a VPS.
There is nothing worse for this, simply because you don't know how many other customers are on your server (keyword: overselling). The more users are on the same core(s) the less CPU is available for you. And if some of them are using them to the max the worse your experience will be.
Do yourself a favor and rent either a complete root server, so you are the only user on it (and so can exactly see what resources you have and use) or rent a game-server from a game server company. They know what hardware you need to have to run your server and can at least argue with them if your server is laggy / choking or whatever as their servers are supposed to host game-servers.