Screen Refresh Rates
|Refresh Rate||Screen Resolution|
|Zune 30||60 Hertz||240 x 320|
|Zune 4, 8, or 80||30 Hertz||240 x 320|
Developers may notice performance differences between the Zune 30, and the Zune 4, 8, and 80. While the hardware of the two devices is similar, screen refresh rates are more frequent on the Zune 30. In terms of actual performance, however, the difference between the Zune 30, on the one hand, and the Zune 4, 8, and 80, on the other, is nearly imperceptable.
The screen resolution on all devices is exactly the same: 240 x 320. On Zune 30, the screen refreshes at 60 Hertz or 60 times a second. On Zune 4, 8, and 80, the screen refreshes at 30 Hertz or 30 times a second. The less-frequent refresh rate saves battery life on the Zune 4, 8, and 80. Prolonging battery life is a major benefit for users.
Internally, the XNA Framework is optimized to save Zune battery life. A call to Game.Draw Method is not worthwhile unless the screen can refresh. For example, if the screen can only draw a sprite 30 times in one second, it would waste processing power and battery life to draw the game screen 45 times in one second. Update will still be called as much as possible regardless of the screen refresh.
Code that calculates frames per second (FPS) in a Draw loop will show close to 60 FPS on a Zune 30. That same code will show close to 30 FPS on a Zune 80. This difference provides savings in battery life, a critical performance metric on a mobile device.
Processors in all versions of the Zune device are similar enough to be considered virtually identical. However, the processor in the Zune 4, 8, and 80 runs at 399 MHz, and the processor in the Zune 30 runs at 524 MHz. This difference gives the new series of Zune devices more battery life.