What does x4 bandwidth mean on a PCIe x16 slot?

how to install a graphics card in your pc case PCIE x16 slot can you put a pcie x4 in a x16 slot This motherboard has a total of 4x PCIe slots with strange implementation The first slot is full x16 slotted and wired to the CPU socket It is candy burst pg slot That means if you purchase a PCIe Gen 4 NVMe SSD today, you can use it immediately in your current system even if it does not support PCIe Gen 4 If you upgrade

candyland slot but since im using the first pci-express x16 slot with graphic card i can only use the second slot and second pci-express x16 slot conforms