The ASUS Maximus IV Extreme comes with four PCI Express x16 slots, one PCI Express x4 slot, and one PCI Express x1 slot. As you can see, this motherboard doesn’t have standard PCI slots.
This motherboard uses an unusual configuration for its PCI Express x16 slots.
The first and the third PCI Express x16 slots are connected directly to the CPU integrated PCI Express controller. When only one video card is installed, the first slot works at x16 speed, but when you install two video cards, the first and the third slots work at x8 speed. When installing two video cards, this is the configuration you should use.
The second and fourth PCI Express x16 slots are controlled by an NVIDIA NF200 chip, and work at x16 speed. When installing three video cards, you must install the first one in the first slot, the second one in the second slot, and the third one in the fourth slot (and not in the third, as it would be the logical assumption). This happens because when installing a dual-slot video card in the second PCI Express x16 slot, you “kill” the third PCI Express slot.
Even though this motherboard has four PCI Express x16 slots, you can only install up to three video cards.
The PCI Express x16 slots support both SLI and CrossFireX technologies.
One advantage of this motherboard is that you won’t need a case with eight or more expansion slots if you decide to install three dual-slot video cards; the system will fit a standard seven-slot case.
This motherboard has two peripheral power connectors to provide more current to the PCI Express slots. One is located near the first PCI Express x16 slot, while the second one is located near the PCI Express x4 slot.
The Maximus IV Extreme has four switches near the first memory socket for you to enable or disable each PCI Express x16 slot. This allows you to detect which video card is malfunctioning without having to remove all video cards from the computer.
In Figure 4, you can see one of the highlights of this motherboard, the NVIDIA NF200 chip.
Besides the NVIDIA NF200 chip, the ASUS Maximus IV Extreme comes with a PLX PEX8608 switch chip, allowing the motherboard to automatically “give” PCI Express lanes to the devices that need more bandwidth. On motherboards that don’t have this chip, you need to manually disable devices on the motherboard setup to give more bandwidth to other devices.