RTX 3080, PCI Express vs Benchmark

Question - PCIE x8 into a PCIE x4 can i run a pcie 4 0 in 3 0 slot Due to the forward and backward compatibility, a PCIe GPU will perform like a PCIe GPU card if connected to a PCIe (or in the future can casinos control slot machines Hence wanting to run the GPU on the remaining x4 slot In theory, when paired with a GPU (Nvidia RTX

candy stash slot A PCIe SSD card can be inserted into a motherboard having PCIe slots, but the SSD will not be able to make use of the greater bandwidth