Also, differences in generation can cause incompatibilities even among slots of the same kind. For example, a PCIe 4.0 card can usually function in a rani modernPCIe 3.0 slot, but bandwidth constraints may prevent it from performing as well as it could. The motherboard's chipset and firmware are another element causing incompatibilities. Due to outdated BIOS versions or chipset limitations, some motherboards might not be able to support all expansion cards.