What is the difference between PCIe NVMe and 2280

I have M2 slot marked as M2X3 What type M2 SSD (SATA, PCIEx nvme vs m 2 slot I want to add SSD drive in my notebook I find M2 slot marked as M2X3 What type M2 SSD can I use? nvme slot 2 SATA Port can only support an SSD That is why the speed can never go beyond 600 MBs Both physically and electrically, any PCIe NVMe

nvme 40 in 30 slot It is a type of PCIe slot drives can use a SATA or NVMe interface SATA ones will have two notches and NVMe will have one