One of the main new features from socket LGA1156 processors is the presence of an integrated PCI Express 2.0 controller inside the CPU. This controller supports one x16 connection or two x8 connections. ASRock P55 Extreme4 has two PCI Express x16 slots using this configuration. They support both CrossFireX and SLI modes, bringing a great advantage over P55 motherboards without support for SLI.
The other PCI Express slots are controlled by the chipset, which has a total of eight PCI Express x1 lanes.
The only drawback we see on this product is that it doesn’t use a PCI Express switch chip (e.g., the PLX PEX8608). When motherboards have USB 3.0 and SATA-600 ports, performance may drop when you use the USB 3.0 ports, the SATA-600 ports and the PCI Express x16 slots all at the same time.
This motherboard has three PCI Express x1 slots and two standard PCI slots. Unfortunately you automatically “kill” one of the PCI Express x1 slots whenever you install a dual-slot video card in the first PCI Express x16 slot.