Can I install PCIe x8 expansion card in a PCIe x4 slot on a QNAP NAS

pcie 8x slot   Dan pcie slot cover

PCIe Slot Number, CPUPCIe Port, PCIe version, PCIe Slot Size, PCIe Lanes ; 2, DMI2, , x8, x4 ; 3, DMI2, , x4, x2

There are two components to a PCIe slot: mechanical and electrical For instance, you can have a slot that is x16 mechanical A PCIe x1 adapter can fit in an x1 or higher slot A larger card, such as a PCIe x16, cannot fit in a lower-numbered slot

the hand of midas slot png PCI-Express PCI-E 8X Slot to PCIe X8 Adapter Converter Card Right Angle 90 Degree for 1U 2U Computer Case, You can get more details about PCI-Express PCI-E Basic adapters, which simply run traces from each connector directly to corresponding lanes on the PCIe slot , #1 goes to the first