Don't be buffaloed by leaks and rumors—the first official announcement of retail Socket AM4 motherboards for AMD Ryzen processors is here. In a weirdly-apropos manner (given the company's Racing theme), Biostar is first out of the gate with its announcement of five AM4 mobos. Three of the boards are based on the high-end X370 chipset, while the other two use the B350 chipset. Let's take a closer look.
The range-topping Biostar Racing X370GT7 is a full-sized ATX motherboard with the sort of feature set you'd expect from a high-end offering. You get a pair of USB 3.1 ports (in Type-A and Type-C flavors), a trio of PCIe x16 slots, and a quartet of DDR4 DIMM sockets that support transfer rates of up to 2667 MT/s. Like on a typical Intel desktop board, two of the PCIe x16 slots will run at x8 when two graphics cards are in use. Biostar makes no mention of Crossfire or SLI support, though. There's a PCIe x4 M.2 socket, six SATA 6Gbps ports, and six USB 3.0 ports, plus an internal header to connect two more USB 3.1 ports. Realtek's fancy ALC1220 offers 8-channel audio, and an RTL8118 controller powers the Gigabit Ethernet port.
Unusually, Biostar equips this range-topping motherboard with a pair of legacy PCI slots. The board also has DisplayPort, HDMI, and DVI-D connectors despite being ostensibly intended for the forthcoming Summit Ridge Ryzen processors that don't include integrated graphics. Those ports can still be used with a Bristol Ridge socket-AM4 APU, of course. Like it did with its Kaby Lake motherboards, Biostar added diagnostic LEDs and a "GT Touch" panel with on-board reset and power buttons. Naturally, the board also includes Vivid LED DJ on-board RGB LED lighting and Biostar's 5050 LED control header.
The Racing X370GT5 is similar to its bigger brother above but drops the second PCIe 3.0 x16 slot. That leaves it with a single PCIe 3.0 x16 slot, plus a PCIe 2.0 x16 slot that runs at x4 speeds. This boasrd keeps its same four USB 3.1 connectors, the full-speed M.2 connector, and the two legacy PCI slots present in the GT7. However, the audio chip gets a downgrade to Realtek's ALC892, and there are no onboard debug LEDs or a DisplayPort connector. The product shots for the GT5 do appear to show a mini-Displayport connection on the back panel, but it isn't mentioned in any of the product documentation.
Stepping down once more to the Racing X370GT3, we move to a microATX design. This board has a feature set almost identical to the GT5, save for the omissions of the GT Touch panel and the two legacy PCI slots.
Judging by their spec sheets, the two B350-based motherboards from Biostar appear to be fairly similar apart from their respective size difference. The B350GT5 is an ATX motherboard that includes a pair of legacy PCI slots and both Type-A and Type-C USB 3.1 ports. Meanwhile, the B350GT3 is a microATX motherboard with no PCI slots and with two Type-A USB 3.1 ports. In an odd twist, the product images for the B350GT5 don't show any USB 3.1 ports at all, while the B350GT3's product images contain that mysteriously-unmentioned mini-DisplayPort like the GT5 and GT3 boards above.
It's hard for us to say whether the tables or the pictures are more accurate. In any case, Biostar's AM4 motherboards look pretty similar to the company's offerings for Kaby Lake apart from those old-school PCI slots. There's no pricing or availability info for these boards, but the company will be offering a 240GB M200 SSD with the top-end X370GT7 model when they arrive.