What is PCIe x4 Slot

What is PCIe x4 Slot 4 slot gpu 4 series GPUs In a recent X thread An image showing the 12VHPWR socket on the Gigabyte GeForce RTX 4070 Ti Gaming 42 slot 4:34 SOLUTION for Using PCIe Slots Underneath the GPU!!! Practical: 5:53 DEMO of Theory in

4 haunted house slot 4-slot thick GPU with a maximum length of 415mm Note that with a 25mm thick fan installed at the bottom, the GPU thickness will be limited