One of the major changes from the Raspberry Pi 3's predecessor - the Raspberry Pi 2 - is the move to upgrade the core Broadcom chip.
The Pi 3 sees the board move to a 1.2GHz quad-core 64-bit ARM cortex A53 CPU. Not only is the CPU faster than the Pi 2's 900MHz quad-core ARM Cortex-A7 CPU, but it is based on an architecture that can do more in each processor cycle. A 400MHz VideoCore IV multimedia processor handles the Pi 3's graphics.
The new CPU core in the Raspberry Pi 3 performs 50-60 percent faster in 32-bit mode compared to the Raspberry Pi 2 and roughly ten times better than the original single-core Raspberry Pi in a multi-threaded CPU benchmark like SysBench. Compared to the original Pi, real world applications will see a performance increase of between 2.5x - for single-threaded applications - and more than 20x - for NEON-enabled video codecs.
Image: The Raspberry Pi Foundation