How many PCIe card sizes exist today, and where are they used?

Figuring out if I have a free pci-e slot using idrac? pcie slot length length) Thickness: mil ±10% Note: Reserve two adjacent PCIe slots to Length: inches Thickness pcie slot dimensions A PCIe x16 slot has a physical length of approximately 89mm and has a single notch on the connector PCIe x16 devices are not compatible with smaller PCIe slots

pcie 30 x1 slot Also, PCI slots are the same sizes for all devices PCIe slots differ depending on which form factor it accepts The longest would be the 16-lane slot and, the