Key difference between DDR4 and DDR3 RAM

No The sticks are physically different DDR4 wont fit in a DDR5 slot and vice versa

Just to clarify DDR5 is not backwards compatible with DDR4, it's a completely different DIMM slot There will be DDR4 and DDR5 Alder Lake

ddr5 slot compatible with ddr4 As noted already, DDR5 uses a different operating voltage than DDR4, has a different architecture, and has the key slot in a different location

ddr5 slot DDR5 motherboards support DDR5 only DDR4 is not compatible with any of them For DDR4 support you need Z690 DDR4 motherboard This one for