According to details that can be seen in the leaked slides by El Chapuzas Informatico and spotted by Videocardz.com, the B450 chipset from AMD will be quite similar to the B350, at least when it comes to specifications, offering overclocking support, a single PCIe slot, two SATA 6Gbps, single SATA Express port, up to two USB 3.1 Gen2 10Gbps, two USB 3.1 Gen1 5Gbps, and six USB 2.0 ports.
The AMD B450 chipset will support Crossfire but the SLI support is still limited to the X470 chipset motherboards.
What makes the B450 chipset special is the support for all improvements and optimizations that came with AMD's 400-series chipset, including an advanced design with optimized VRM, better memory support, advanced efficiency and USB support and advanced storage support with bootable NVMe RAID support and AMD StoreMI.
It will also support AMD's latest XFR2 Enhanced and Precision Boost Overdrive technologies.
Unfortunately, there is no information on when we can expect first B450 motherboards to hit retail/e-tail shelves but the same source suggests that Asrock is working on no-less than four different B450 motherboards, so there should be plenty to choose from.