ot only is the Raspberry Pi 3 Model B the fastest Raspberry Pi to date, it's the first one with built-in WiFi (802.11B/G/N) and Bluetooth Low Energy1 connectivity allowing you to get connected right out of the box.
The Pi 3 is powered by an all-new BCM2837 1.2GHz Quad-Core ARMv8 64bit2 processor that is noticeably quicker and more usable than previous generations. Webpages render faster and programs are much more snappy, making the experience feel like a modern machine than a $35 computer.
Other upgrades include improved power management which allow the Pi 3 to power hungry USB gadgets like hard drives and cameras. Of course, this increased capacity means that you'll need a power supply that's up to the task. We recommend a 5V USB power supply capable of putting out at least 2.4A. If you're looking for one, our 28-19336 5.25V 2.4A supply has been heavily tested to be compatible with the Pi 3.
Another slight upgrade is to the microSD card port. The spring loaded pop-in, pop-out port has been replaced with a simpler (and more reliable) manual side-in, slide-out version. This will be a welcome change to anyone who's popped-out the microSD card accidentally!
Upgrades above aside, the rest of the Pi 3 is very similar to previous generations. RAM stays the same at 1GB, Ethernet is 10/100 and the GPU is the same tried-and-true VideoCore IV. As for physical changes, the Pi 3 keeps the same footprint, mounting holes, and all port types and locations as previous versions. The only physical difference is the addition of a ceramic WiFi / BLE antenna and the location of the status LEDs (which have switched sides.) All cases that worked for the Pi B+ and Pi 2 are compatible (although you may want to drill new holes to see the status LEDs.)