Is all ddr4 so dimm ram the same?

Introduction to DDR5 Memory ddr4 and ddr5 same slot Bought a MSI Z790 Edge d4 board and some ddr4 memory While at Microcenter I had them test my ddr5 ram ddr4 slot vs ddr5 No, it won't Even though both types have 288 pins, DDR4 and DDR5 memory is electrically incompatible The two types have a different notch

ddr4 sodimm slot But unlike DDR4 which introduced more pins, DDR5 still sticks to the same 288 pin arrangement DDR5 memory module into a DDR4 slot, or vice-