The ASRock X570M Pro4 is a full width (9.6 inch) Micro-ATX form factor board. It has a black PCB which ASRock calls ‘Sapphire Black’. The PCB itself is 2oz copper layered, but doesn’t feel quite as heavy as some premium boards.
Read more @ PC Perspective
Engineered around the AMD X570 chipset, the Pro4 is ready to accept any of the Ryzen 2nd or 3rd Gen. CPUs, up-to and including the upcoming Ryzen 3950X. With the X570 chipset comes a plethora of next-gen features, one of which is the PCI-E 4.0 standard, offering double the bandwidth of the outgoing specification, but with full backwards compatibility.
Read more @ Vortez