Hi Tech Legion posted a review on the MSI P55-GD85 USB and SATA 3.0 Motherboard

Unlike some other manufacturers, MSI has chosen to use the built in PLX chip, specifically for Marvel and NEC, to provide for SATA and USB 3.0 performance. The PLX PCI-e bridge chip is specifically designed to increase (multiply) bandwidth and effectively distribute that bandwidth across the PCI-e lanes when using the 3.0 functions. Other manufacturers have chosen to forgo the PLX, which forces USB and SATA 3.0 to occupy the graphics PCI-e lanes causing a bottleneck and decreasing graphics performance.

MSI P55-GD85 USB and SATA 3.0 Motherboard Review