The Gigabyte F2A85X-UP4 comes with three PCI Express 2.0 x16 slots, three PCI Express 2.0 x1 slots, and one standard PCI slots.

The first two PCI Express 2.0 x16 slots are controlled by the CPU, with the first slot working at x16 when only one video card is installed, and with both working at x8 when two video cards are installed. The third PCI Express 2.0 x16 slot is controlled by the chipset and always works at x4. These slots support the CrossFireX technology. If you want to install a dual-slot video card in the third PCI Express 2.0 x16 slot, you will need a computer case with at least eight slots. (Cases usually have seven.)

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Figure 2: Slots