iOS4 controller performance

I am creating an game application for iPhone that use开发者_运维知识库s two controllers. One for the main view which basically is som buttons to start the game.

The game is a game that renders in drawRect and is therefore quite performance critical. My question is: Are there any performance cons to use

[self presentModalViewController:tmpControler animated:NO];

When switching from the main view controller to the "game controller"? Or should I use another way?