Last month the first OEM PCs with AMD's Bristol Ridge hit retail stores. Bristol Ridge is the first AMD chip to use the new Socket AM4, it's basically an updated version of Carrizo and we're still not quite sure when or if the AMD "Bristol Ridge" APUs will see standalone retail availability.
The first Zen-based chips are expected in early 2017 and the first Socket AM4 motherboards are hitting the channel. TechPowerUp spreads photos of two Gigabyte motherboards, one seems to use the entry-level A320 chipset while the other one sports the mid-range B350 chipset.
The first of the two GIGABYTE AM4 boards is built in the narrow micro-ATX form-factor; featuring a single PCI-Express 3.0 x16 slot, two DDR4 DIMM slots, four SATA 6 Gb/s ports, and basic connectivity that includes 6-channel HD audio, one gigabit Ethernet connection, and 4-6 USB 3.0 ports. The second board is better endowed, and is likely a variation of the socket AM4 board that was earlier pictured this September. It features two PCI-Express 3.0 x16 ports (the second one could be electrical x4); and comes with two additional SATA 6 Gb/s and USB 3.0 ports compared to the other board.
The new high-end chipset for AM4 is the X370, we'll probably see a lot of motherboards based on that chip as we get closer to CES 2017.