The A9 chip is a system-on-a-chip designed by Apple for use in its devices, including the iPhone 6s and iPhone 6s Plus. Released in 2015, it features a 64-bit architecture and is built using a 14-nanometer process, which enhances performance and energy efficiency compared to its predecessor, the A8 chip. This chip includes a dual-core CPU and a quad-core GPU, allowing for faster processing and improved graphics performance. The A9 also supports advanced features like Apple's Siri voice assistant and enhanced camera capabilities, making it a key component in delivering a smooth user experience across various applications.