The A4 combined an ARMA CPU architecture family known for energy efficiency — dominates smartphones and growing in servers and laptops. Cortex-A8 CPUCentral processing unit — the primary chip that executes program instructions. with PowerVR graphics in a package Apple designed — not just rebranded Samsung silicon. It shipped in the iPadApple's tablet computer line — larger touch screens between phones and laptops. and iPhoneApple's smartphone line — touch-first mobile computing and the App Store ecosystem since 2007. 4, starting Apple's vertical integration of mobile chip design. Every A-series and M-series chip since traces to this SoC strategy.

The A4 was Apple's first custom SoC — the start of in-house mobile silicon.

It let Apple tune CPUCentral processing unit — the primary chip that executes program instructions., GPUGraphics processing unit — a chip optimized for parallel math; now used for graphics, ML, and scientific computing., and power together for iOSApple's mobile operating system — runs iPhone and iPad with a sandboxed app ecosystem. devices instead of relying on off-the-shelf chips.