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. MSI P55-GD85 has two PCI Express x16 slots using this configuration. GD80 from the same manufacturer has three PCI Express x16 slots, but this third slot works at x4. The portrayed motherboard also has two PCI Express x1 and two standard PCI slots, the same amount present on GD80.

This motherboard from MSI supports both CrossFire and SLI configurations. Keep in mind that SLI support on P55-based motherboards will depend on whether the manufacturer licensed this technology from NVIDIA or not, i.e., not all P55-based motherboards have SLI support. On the MSI line-up P55-CD53 and P55-CD45 do not support SLI.

MSI P55-GD85 motherboardFigure 2: Slots.

Another small but very important detail is that MSI added a PLX PEX8608 PCI Express switch chip on this motherboard, which adds eight more PCI Express lanes to it. The presence of this chip allows you to run two high-end video cards, SATA-600 hard disk drives and USB 3.0 devices at the same time without any drop in performance. On motherboards without a chip like this, performance may drop under this type of load, as the chipset doesn’t have enough PCI Express lanes to connect all these devices at the same time at their full speed. P55-GD80 doesn’t have this chip, but this isn’t a problem, since this other board does not have SATA-600 and USB 3.0 ports.

MSI P55-GD85 motherboardFigure 3: PLX PEX8608 PCI Express switch 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.