First off, we have the H170A and B150A Gaming Pro models. MSI has reinforced the main PCIe slot on these boards to prevent heavy graphics cards from bending or separating the slot from the board. MSI taps an Intel controller for Ethernet connectivity, along with anti-surge protection at the port. SATA Express ports handle next-gen storage connectivity. Those who want to install M.2 storage will find themselves out of luck, though.
These boards come with MSI's Audio Boost 3 setup, which brings some perks of its own: isolated circuitry, dual TI OPA1652 headphone amplifiers, and an EMI shield over the audio chip. USB I/O also gets a boost—besides the chipset's USB 3.0 ports, MSI has added two USB 3.1 Gen2 (10Gb/s) ports, courtesy of an ASMedia ASM1142 chip. Last but not least, there's an RGB LED strip on the front of the boards, which MSI calls "Mystic Light." Groovy.
MSI makes a few more tweaks and trims to create the H170 Gaming M3 and the B150 Gaming M3. These are similar to the Pros on the audio front, but they drop the USB 3.1 Gen2 connectivity, SATA Express ports, and the mood lighting. Intel's NIC gets replaced with a Killer Ethernet adapter, and MSI bundles Nahimic's audio enhancer software, as well. Both Gaming M3 boards come with an M.2 slots that can be converted into U.2 ports with an optional adapter.