The AMD Ryzen 7 7700X3D is not explicitly listed in the compatibility lists for the MSI MPG B550 Gaming Plus motherboard. Support for Ryzen 5000 and 3000 series is confirmed, but there is no specific information about compatibility with the Ryzen 7000X3D. It may be necessary to check the BIOS version and update if necessary to ensure the motherboard is compatible with newer processors. For exact information, I recommend consulting the official MSI website or customer service.