PCIe Gen 4 vs Gen 3 Slots, Speeds

Not true You can actually use a PCIe x1 card in a x16 slot While not applicable in this particular case (what with the mini-ITX

No, it is not possible to use a PCIe x16 card in a PCIe x1 slot The physical design and specifications of a PCIe x16 card are different from a

pcie 4 in pcie 3 slot Yes it can be done, provided that motherboard manufacturers provide a space between the slots big enough for your x16 expansion card to fit

pciex4 slot A PCIe slot can support from 1 to 16 lanes Standard PCIe slots include 1, 2, 4, 8, and 16 lanes called PCIe x1, x2, x4, x8, and x16,