Will my graphics card work in all PCIe slots?

Your Ultimate Guide to Understanding PCIe Gen pcie 4 0 in 3 0 slot Yes, it'll be perfectly compatible with gen PCIE slot pcie 40 gpu in 30 slot Best AMD AM4 B550 MATX motherboard, lightning PCIe , lightning , USB Gen 1, heatsink, wifi AC, powerful overclocking, MSI PRO

pcie 30 x1 slot But what about the fallback to PCIe , for example runs an older AMD or current Nvidia graphics card in such a slot? In order to remain really