Note:The MSI MPG Z390 GAMING EDGE AC ATX LGA1151 Motherboard has an additional 4-pin ATX power connector but the Corsair RMx (2018) 650 W 80+ Gold Certified Fully Modular ATX Power Supply does not. This connector is used to supply additional 12V current to the motherboard. While the system will likely still run without it, higher current demands such as extreme overclocking or large video card current draws may require it.Note:The motherboard M.2 slot #1 shares bandwidth with a SATA 6.0 Gb/s port. When the M.2 slot is populated, one SATA 6.0 Gb/s port is disabled.Note:The motherboard M.2 slot #2 shares bandwidth with SATA 6.0 Gb/s ports. When the M.2 slot is populated with a PCIe-based M.2 drive, two SATA 6.0 Gb/s ports are disabled.Note:Some physical dimension restrictions cannot (yet) be automatically checked, such as cpu cooler / RAM clearance with modules using tall heat spreaders.
You can ignore the first note unless you are doing hardcore overclocking and I believe the second note was discussed in another comment. The last one is something every build here has.