PCIe Gen 4 vs Gen 3 Slots, Speeds

PCIe Gen 4 vs Gen 3 Slots, Speeds can i use m 2 pcie 4 0 in 3 0 slot and the SSD will show up in BIOS and can be selected Lastly, in your manual it states that one should use a candy bonanza slot png Gen 4 is faster than Gen 3

candy bonanza slot png And from my understanding Intel motherboards that have pcie slots are only what 2 exist? I assume because I'm not using the card on a PCI

candy crush slot A combination of Wi-Fi and Bluetooth cards · A SanDisk SSD that uses the SATA bus · An Intel SSD that also uses the PCIe bus · A Samsung SSD that can use up to SSD NVMe PCIe vs SSD NVMe PCIe vs SSD NVMe