Learning iOS Development: A Hands-on Guide to the Fundamentals of iOS Programming

Processor Speeds

All modern devices come with fast Apple-designed ARM processors. The CPU includes a good amount of fast access RAM for code execution. To save power, some devices run the CPU at slower speeds (underclocked), and all have the ability to suspend parts of the hardware. Some earlier devices had relatively slow processors and much less execution space though they make up an ever-decreasing part of the market. Targeting iOS 6 or later will avoid those early devices.

The important thing is to run your app on a representative sample of the kinds of devices you are targeting. Make sure it performs well on the devices your customers will use. This is especially important if you plan to support iPhones prior to the 4 as well as first-generation ...