The ASRock Z77 Extreme9 comes with five PCI Express 3.0/2.0 x16 slots, one PCI Express 2.0 x16 slot, one PCI Express 2.0 x1 slot, and one Mini PCI Express slot.

Usually, on motherboards based on the Z77 chipset, only the first two PCI Express x16 slots are controlled by the CPU; the other PCI Express x16 slots are controlled by the chipset, operating at a lower speed (almost always x4) and only compatible with the 2.0 specification, which offers half of the 3.0 bandwidth. On this motherboard, however, thanks to the use of a PLX PEX8747 switch chip, five of the six PCI Express x16 slots are connected to the CPU, and are, therefore, compatible with the PCI Express 3.0 specification. However, “only” four of those five slots can be used at the same time. Keep in mind that the slots connected directly to the CPU will only offer PCI Express 3.0 bandwidth when an “Ivy Bridge” CPU is installed; with a “Sandy Bridge” model they will operate using the 2.0 specification.

The fourth PCI Express x16 slot (PCIE4) is controlled by the chipset, always works at x4 speed, and uses 2.0 bandwidth.

The ASRock Z77 Extreme9 supports the configurations listed below.

x16 x4
x16 x4 x16
x8 x8 x4 x16
x8 x8 x4 x8 x8

If you want to install only one video card, you will need to use the second PCI Express x16 slot and not the first one, as it would be the most logical option. In addition, if you want to install two video cards, you must use the first and the fifth slots, so both can work at x16 speed.

When installing dual-slot video cards, you “kill” the slot immediately to the left (looking at the motherboard with its rear connectors facing up) of the slot being used. Even with this limitation, you will be able to install up to four dual-slot video cards on this motherboard. If a fourth dual-slot video is installed (in the sixth, i.e., PCIE7 slot), you will need a case with at least eight expansion slots.

The PCI Express x16 slots support both SLI and CrossFireX technologies.

ASRock Z77 Extreme9 motherboard Figure 2: Slots

ASRock Z77 Extreme9 motherboard Figure 3: The PLX PEX8747 chip

The Mini PCI Express slot comes with a Wi-Fi card supporting the IEEE 802.11b/g/n standards installed.

ASRock Z77 Extreme9 motherboard Figure 4: Mini PCI Express slot with the Wi-Fi card

In order to properly accommodate the additional PCI Express devices that are on this motherboard (the second Gigabit Ethernet port, the eight additional USB 3.0 ports, the four additional SATA-600 ports, the Wi-Fi card, etc.), the board makes use of a PLX PEX8608 switch chip. This chip automatically switches the available PCI Express lanes to the devices that need them. On motherboards with too many PCI Express devices without a switch chip, you need to manually disable devices on the motherboard setup in order to achieve full performance on devices connected to the USB 3.0 and SATA-600 ports when transferring files at the same time.

ASRock Z77 Extreme9 motherboard Figure 5: The PLX PEX8608 chip


Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.