The compatibility of the ROG Strix B650-A Gaming Wifi motherboard with the Corsair 6500x case depends mainly on the size and specifications of the case. The motherboard is an ATX type, so it should be compatible with most ATX cases. However, it is important to make sure that the case has enough space for the size of the motherboard (30.5cm wide and 24.4cm deep) and that it supports the necessary cooling and power connections.