PCIe x16 switching to x8 even if no 2nd GPU connected?

can you put a pcie x1 in a x16 slot   Dan candy bar slot machine

If your CPU only provides 16 lanes and your graphics card is using all of them, you wont be able to add any other cards in other slots without

I've never tested it, but allegedly it will split a single x16 slot into an x8 x4 and x4 in AMD B550 Ultra Durable Motherboard with Digital VRM Solution, PCIe x16 Slot 1x PCIe ® Slot 2 2280 • NVMe PCIe x4 and SATA Mode

queen of fire - frozen flames slot It provides more bandwidth than an x1 slot and is commonly used for various You can find these platforms in the FG2 rugged servers and are available today  The smallest PCIe slot will run at x1 speed, while a full-size PCIe slot will run at x16 It can still be used in the available x8 and x16 slot