Can someone clarify PCIe terminology of the B450 TOMAHAWK

MSI B450 TOMAHAWK MAX Motherboard Compatible RAMSSDs msi b450 tomahawk max m 2 slot Suitable For Desktop · AMD B450 · Data Rate DDR4 · Maximum RAM Capacity 128 GB · Form Factor: ATX msi slot MSI B450 Tomahawk Max Am4 Socket Ddr4 Motherboard with slot Updated Bios for 1st, 2nd and 3rd Gen AMD Ryzen DDR4 Memory, up to 4133 MHz, Illuminate with

msi a320ma pro m2 slot Faetures: ; Multi-GPU, Supports 2-Way AMD® CrossFire™ Technology ; Storage, AMD® CPU 2 x SATA 6Gbs ports · 1 x slot