Official Raspberry Pi Page
https://www.raspberrypi.org/products/raspberry-pi-3-model-b/
Key Differences To The Raspberry Pi 2
1.2GHz 64-bit quad-core ARMv8 CPU (BCM2837)
Built in 802.11n Wireless LAN
Built in Bluetooth 4.1 and Bluetooth Low Energy (BLE)
Software difference issues we’ve encountered:
UART for Pre RPi3 is “/dev/ttyAMA0”. On the RPi 3 this is assigned to bluetooth and the UART is now “/dev/ttyS0”.
Shared Specifications To The Raspberry Pi 2
Identical form factor to the RPi 2, RPi1 Model B+.
Complete compatibility with Raspberry Pi 1 and 2.
1GB RAM
4 USB ports
40 GPIO pins
Full HDMI port
Ethernet port
Combined 3.5mm audio jack and composite video
Camera interface (CSI)
Display interface (DSI)
Micro SD card slot
VideoCore IV 3D graphics core
Power
http://raspi.tv/2016/how-much-power-does-raspberry-pi3b-use-how-fast-is-it-compared-to-pi2b
USEFUL?
We benefit hugely from resources on the web so we decided we should try and give back some of our knowledge and resources to the community by opening up many of our company’s internal notes and libraries through mini sites like this. We hope you find the site helpful.
Please feel free to comment if you can add help to this page or point out issues and solutions you have found, but please note that we do not provide support on this site. If you need help with a problem please use one of the many online forums.