[jcizzle]

Pretty close on the iOS stuff:

1. All* rendering takes place on the main thread in iOS.

2. The main thread doesn't always have the highest priority. In fact, its priority level changes throughout an application.

3. There is more than just one reason iOS rendering is so fast. Here are two important ones:

a. Animation is actually the basis of the entire rendering system. On desktop Cocoa, the drawing system was a little dated. The mistakes learned from this system and the desire to have fast animation led to the Core Animation framework and the idea of "layers". The ability to quickly composite layers (without moving any data from between the CPU and GPU) and only redraw when necessary is huge.

b. The batching together of drawing updates at the end of an event instead of on an as needed basis allows for huge performance gains.

* It is possible to draw in a background thread, but is reserved for particular situations (maps, web content, etc.). Table views do not fall into this category.

[danssig]

Do you think games will ever take advantage of this on OSX to start giving Apple an edge? Right now I still have to have a Windows machine if I want to do any gaming.

[jcizzle]

When it comes to games, OpenGL is still the best option. The animation system works well for moving around interface elements in two dimensions. The animation system does not work well for 3D or when you are modifying the bitmap content of a layer on the screen.

Will OSX ever catch up to Windows for games? Maybe. Some game companies take the approach of writing everything in OpenGL to make it easier to port between systems, writing a layer of native code to support their cross-platform code.

However, some studios use DirectX which is windows-only. The popularity of OSX and iOS will only increase the pressure on game developers (and engine developers) to write code that is easier to port.