Does it matter which PCIe slot I put my graphics card in?

The slot# to pcie bus# mapping should be in the server docs If not, you'll have to document it yourself on first install which pays off if

PCIe versions can ABSOLUTELY affect your performance If you've bought a PCIe card and expect it to perform in a PCIe or PCIe slot

does ddr5 fit in ddr4 slot If the PCIe slot has x16 mechanical and x8 electrical, you can have 16 cards, but performance gets halved due to half the lanes That is how you can fit a PCIe

does it matter which gpu slot i use In this video I tested the rendering speed of a GTX 1060 when plugged into a 16X PCIe slot