Will a Samsung 860 EVO M.2 SSD work with the Gigabyte B850 AORUS ELITE?

Your 860 EVO is an M.2 SATA drive rather than an NVMe drive. You can use it with an M.2-to-SATA adapter connected to one of the motherboard’s regular SATA ports, but buying an NVMe M.2 SSD would be the cleaner option for the board’s M.2 slot. A standard 2.5-inch SATA SSD would also connect directly to the SATA ports.

The motherboard does have SATA ports, so it can work with a SATA SSD. However, the built-in M.2 slots on this board support NVMe drives, not M.2 SATA drives. That’s likely why the compatibility checker is warning you.

There isn’t a problem with the Samsung drive itself; it’s just using a different M.2 protocol. M.2 describes the physical size and shape, while SATA and NVMe describe how the drive communicates. Make sure any replacement drive is labeled PCIe NVMe if you want to install it directly into the motherboard’s M.2 slot.