Yes, you can install a 1x PCIe card into a 16x or 4x PCIe slot

Yes, you can install a 1x PCIe card into a 16x or 4x PCIe slot 4x pcie slot Buy Black New High Quality NGFF To PCI-E 4x 1x Slot Riser Card Adapter M2 To PCIE X4 X1 Converter For Graphics Card at the lowest price 4xbet slot PCIe x4 is mostly for server grade network cards

4xbet slot Most of the time it works fine but some mainboardvideo card combos won't see a 16x card in a 1x or 4x slot due to the PCIe presence detect not

4x4 super slot PCI-e slot on your motherboard and these only run at 8x or even 4x speeds, they will still work, but performance can be lower than in a full speed slot  Upstream port: PCIe x8 Edge Finger · Downstream port: Two Internal PCIe Cable Port · PCI Express Switch: 16-Lane, 5-Port PCIe Gen 3