How to identify CPU and memory usage per process on iPhone?
Xcode has an app called Instruments and you can use it to gather all sorts of CPU and memory statistics both live as the device runs and to save for analysis over time. This use of the tool doesn't require a developer account, any paid software, or a jailbroken device. You do need to set up the devices in Xcode's organizer to indicate you wish to use them for development and connect them via USB - just cancel out of any requests to manage certificates or developer profiles as you add each device to Xcode's organizer.



Above is a one click, capture and you can dive as deep as I could imagine anyone needs by selecting extra data to be sampled and displayed...