How to buy a computer that supports multiple monitors?

if you're buying a desktop computer check the graphic card: if it's integrated it (usually) doesn't support multimonitor configurations.

if it has a separate graphic card check the model of the card; then look at the card specifications (note that "nvidia gt630" isn't enough.. producers use that chipset on different boards!!!). however.. nowadays only really cheap cards has only one monitor connector! with 50$ you can buy a "decent" card (if you don't play games with your pc!)

if you're buying a laptop: usually they have one dvi/vga connector for the 2nd monitor and the integrated monitor..

Two monitors is simple for modern computers to accomplish. If you want more than two you will need to make sure you get a graphics card strong enough to support it, as well as the proper connectors.

For two monitors though, Just make sure that it includes the necessary ports. Most bargain PCs only provide one Video out port. If this is the case you will need to purchase either an internal graphics card with the needed ports, or buy a USB->Video converter (cheaper, but not as nice of a picture.)

For laptops, look into docking stations. These almost always provide at least two video ports for the purpose of multiple monitors.

In this day & age, if the card has multiple outputs, it can support multiple monitors. ATI/AMD cards can drive up to 6 outputs independently, while nVidia cards can drive 2 independent outputs (or 3 joined outputs + 1 independent output - see "nVidia 3D surround" for info. These limits are per-card if the system has multiple graphics cards acting independently, or per-cardgroup if you're working with SLI). Intel's integrated graphics (GMA, or the newer graphics that come with sandy bridge and ivy bridge processors) can drive at least 2 monitors.

On a laptop, if the system has an external connector for the monitor, it can drive the internal display + an external monitor. Driving multiple external monitors, or with a docking station makes things more tricky and vendor-specific.

Pretty much any system or graphics card you buy new today will support at least 2 displays as long as you have a place to actually hook up the second display.

Well for just a computer that can support dual monitors, you want to look at the adapters.

Video Port Reference from DoctorMo

Basically you want a video card that has two of one of the above ports. The best bets would be two of one kind, since you then know that they are compatible. Two VGA (older video), two DVI (higher end video), one DVI and one VGA (mid range video).

Try and make sure at least two of the ports are in a similar area of the back. If one is up high on the back and one is down low, the computer likely has an onboard and dedicated video card, which may or may not work as a dual-monitor computer.

Only go for the HDMI or S-Video if you know you can support those output types, which usually requires a semi-modern or modern television.

Most modern monitors use the large DVI interface, but there are adapters between DVI and VGA.

If you are interested in learning more about ports, visit the source of the above image at their page.