Choosing the video card(s)

If you want to use 2 monitors, you may not have to buy additional hardware: laptops usually support a second monitor out of the box via the external VGA connector, and desktop systems are frequently equipped with dualhead (2-monitor) video cards as well.

For more on adding additional monitors to a laptop, see Laptops. To add additional monitors to a desktop, you can either replace your existing video card with one which supports more monitors, or install one or more PCI video cards.

Multi-monitor video cards support 2, 4 or 8 monitors, and are usually available in both AGP and PCI versions. You can also install multiple multi-monitor cards, for example a system with 16 monitors could be set up with 1 AGP quad (4-monitor) card + 3 PCI quad cards.

When more than one video card is installed, one of the cards will be used as the BIOS primary video card. This is the card which is active during system startup and displays BIOS messages and the Windows boot progress, and it is also the card which will be used for fullscreen DOS applications.

The BIOS primary card is either the AGP card or the first PCI video card (the one in the lowest-numbered slot, nearest to the AGP slot). To choose whether AGP or PCI should be primary, enter the BIOS setup during booting and look for a setting called 'Initialize First', 'Init Display First' or similar.

Recent PCI video cards usually work fine as secondary, but some configurations might not work. Nvidia and Matrox cards usually work well, ATI is a bit less reliable. You should research your desired configuration in the compatibility database before purchasing.

Please note that old PCI video cards (S3 Trio, ATI Rage, etc) need to be primary in BIOS in order to work with Windows 2000/XP and later. Because only a single card can be primary in BIOS, this means that you're limited to a single card of this type per system.

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