There's a common misconception about the way games are built, explained Greenawalt. Gamers will often speak of games failing to use the full power of a given console, but the reality of development is quite different.

"When it comes to hardware you always use 100 per cent. Even to make a little arcade game, you'd use 100 per cent of the hardware. But when you're first party, and when you've got a really clever development staff that's world class, hired from all over the industry, then you learn tricks. It's like Tetris.

"With Forza 2 we were the first game on the 360, at least that I know of, that could do 60 frames per second. And we did a lot of things wrong when we built our model. We did some things right, but just like a jigsaw puzzle, the first time you build it, it takes an hour, and the second time you build it, it takes half an hour. Eventually it just takes 15 minutes, because you learn how to build it faster."