The Raspberry Pi 3 is the third generation Raspberry Pi. It replaced the Raspberry Pi 2 Model B in February 2016. Compared to the Raspberry Pi 2 it has: A 1.2GHz 64-bit quad-core ARMv8 CPU 802.11n Wireless LAN Bluetooth 4.1 Bluetooth Low Energy (BLE) Like the Pi 2, it also has: 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 (now push-pull rather than push-push) VideoCore IV 3D graphics core
The Raspberry Pi 3 has an identical form factor to the previous Pi 2 (and Pi 1 Model B+) and has complete compatibility with Raspberry Pi 1 and 2.
We recommend the Raspberry Pi 3 Model B for use in schools, or for any general use. Those wishing to embed their Pi in a project may prefer the Pi Zero or Model A+, which are more useful for embedded projects, and projects which require very low power.