The ASUS P8P67 Deluxe comes with three PCI Express x16 slots. The first two (the blue one and the light gray one) are controlled by the CPU, not the chipset. The first slot (blue) works at x16 when only one video card is installed, but it drops to x8 when a second video card is installed. The second slot (light gray) works at x8. The third slot (black) is connected to the chipset and works at x4. These slots support both SLI and CrossFireX modes.
ASUS made a terrific job using different colors for each PCI Express x16 slot, this way you can easily identify the speed each one of them run at.
If you install a dual-slot video card in the first PCI Express x16 slot you will “kill” one of the PCI Express x1 slots, while if you install a dual-slot video card in the second PCI Express x16 slot you will “kill” one of the standard PCI slots. You can only install a dual-slot video card in the third PCI Express slot if you have a case with eight or more expansion slots (cases usually have seven expansion slots).
It is important to understand that the P8P67 Deluxe has two slots between the first two PCI Express x16 slots, meaning that you can install a video card that occupies three slots in the first PCI Express x16 slot and still install a second video card in the second PCI Express x16 slot.
The motherboard has two PCI Express x1 slots and two standard PCI slots.
It is important to understand that the P67 and H67 chipsets don’t support standard PCI slots anymore, and the PCI slot is provided by an ASMedia ASM1083 bridge chip.
The ASUS P8P67 Deluxe uses a PLX PEX8608 switch chip, which expands the number of PCI Express lanes available on the motherboard and allows all high-bandwidth devices (i.e., USB 3.0 and SATA-600 devices) to be used at the same time without impacting performance.