3 Things to Know About the MSI PRO B660M-G's Expansion Slots
One PCIe 4.0 x16 slot This single slot runs at full Gen 4 bandwidth, so a modern graphics card won’t be bottlenecked.
One PCIe 3.0 x1 slot This is for a modest expansion card like a Wi-Fi adapter or sound card.
No extra PCIe slots The micro-ATX board keeps expansion simple, which is expected at this price tier.