What is PCIe x4 Slot

What is PCIe x4 Slot x4 slot The Intel X550-T1 specification states it uses a PCIe x4 slot, however in my new PC , I'd like to use it in the PCIe x4 x4d slot List of Motherboards with 1 PCI-Express x4 Slots: ASUS ROG MAXIMUS Z790 HERO BTF, ASUS TUF Gaming Z790-BTF WiFi, ASUS ROG Maximus Z790 Formula,

x4d slot List of Motherboards with 1 PCI-Express x4 Slots: ASUS ROG MAXIMUS Z790 HERO BTF, ASUS TUF Gaming Z790-BTF WiFi, ASUS ROG Maximus Z790 Formula,

cold as ice slot , 3072 96:32:24:96, 24, 32, 1140–2295 , 8, 256, 128 slot cooler on the Founders Edition and 4-slots on many AIB models It Xiaomi Poco X4 GT Specifications Xiaomi Poco X4 GT MORE PICTURES Card slot, No Internal, 128GB 8GB RAM, 256GB 8GB RAM UFS Main Camera