What kind of expansion slot should you use for your video card?

I get slot Slot 1-3 with dmidecode lspci -s with these slot numbers return me each two devices from type PCI bridge If I use

A slot that uses a 66 MHz PCI clock, always will use Volt signalling In fact there is no way to see from the connector if a slot is using a 33 MHz clock or

gpu expansion 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

gpu with m2 slot Then, it's the turn to introduce PCIe slot This slot has 7 versions: x1, x2, x4, x8, x12, x16, and x32, corresponding to 1248