Basic Specifications

• Both the A4 and A5 chips are 1-gigahertz chips, but the A5 is a dual core processor. This makes it work approximately twice as fast as the single-core A4. Both chips are less than .2 square inches in size, but the A5 is significantly larger than the A4 at 122 square millimeters compared to the A4's 53 square millimeters. This small physical size is designed to let the chips operate the iPad without taking up valuable space inside, needed for Flash memory modules or battery components.
  
  

IPad Chips on Other Devices

• A few of Apple's other devices also use the A4 chip, including the iPhone 4 and Apple TV 2. Future versions of these devices may use the A5 chip. However, the chips are released first in the iPad models and designed to give a balance of performance and battery life when used with the iPad's large screen and varied software capabilities.
  
  

ARM Technology

• The A4 and A5 chips use ARM architecture, meaning that the chips use technology developed by the ARM company for the core processors of their chips. This technology focuses on minimizing the power consumption on chips for mobile devices, and it is used by a variety of smart phones and tablet computers. ARM labels their processing cores similarly to Apple, so the Apple chips may use A8 or A9 cores from ARM, but this is not related to the Apple designation of an A4 or A5 chip.
  
  

Manufacture

• Samsung manufactures the A4 and A5 chips for Apple, despite that company's own tablet that was launched as an iPad competitor. However, legal disputes between the two companies over patent infringement may result in future iPad chips being manufactured by a different company.