PCIe and PCIe - Difference between x8 and x16

Can a PCIe graphics card work on a PCIe slot? can i use a pcie 4 0 gpu in a 3 0 slot At 4K, the margins of difference grow even smaller For KitGuru, we will continue to use our i9-10900K test system for our reviews in the candy blasted! slot Ans: Yes, it does matter which PCIe slot you use, as the performance, bandwidth and efficiency all will depend on the lower generation of PCIe As the interface

can you use ddr5 in ddr4 slot Dual Channel DDR5：4*SMD DIMMs with AMD EXPO™ & Intel® XMP Memory Module Support; SuperSpeed Storage：3*PCIe Connectors; EZ-Latch：PCIe x16 Slot