This refers to the quad-core Raspberry Pi 2 (currently only available as a "B" model with Ethernet and four USB ports), with 1 gigabyte of RAM.
The Raspberry Pi 2 Model B differs from the Model B+ in two major points:
- A 900 MHz quad-core ARM Cortex-A7 BroadComm 2836 CPU
- 1 GB of RAM
The Raspberry Pi 3 Model B differs from the 2 B:
- A 1.2 GHz quad-core ARM 7 BroadComm 2837 CPU
- A Broadcomm BCM43143 to provide the USB Hub / Ethernet/ 2.4 GHz Wi-Fi / Bluetooth - replacing the LAN9512 or LAN9514 of previous 2 / 4 USB / Ethernet "B" Pi models.