AMD 890FX chipset has 42 PCI Express x1 lanes controlled by 11 engines – just to put things into perspective, the AMD 890GX chipset has 22 lanes controlled by eight engines. This allows this chip to provide a very high-end slot configuration.
The ASRock 890FX Deluxe4 comes with three PCI Express x16 slots. The first two always work at x16, regardless of the number of installed video cards. The third slot, labeled PCI5, always work at x4. On the 890FX Deluxe3 model the third slot is white instead of blue, making it easier to identify the slower slot, but on the new Deluxe4 all slots are blue. All slots support CrossFireX mode, as expected, but not SLI.
The PCI Express x16 slots have enough space between them for you to install up to three dual-slot video cards. However, to install a dual-slot video card on the third PCI Express x16 slot you will need a case with at least eight expansion slots, and it will cover two SATA-600 ports, the serial port header, floppy disk drive port, the front panel header, frontal USB 3.0 header, the power and reset buttons, and the POST diagnostics display. By installing a dual-slot video card in the first PCI Express x16 slot you will cover the PCI Express x1 slot that is to its left, while installing a dual-slot video card in the second PCI Express x16 slot you will cover one of the standard PCI slots.
This motherboard also comes with two PCI Express x1 slots and two standard PCI slots.