docduke

I have a Radeon 9550 video card which has one analog and one digital output. I bought a second analog monitor (cheaper than digital) so I could double the screen real-estate. All that was required was an adaptor to plug the second analog monitor into the digital plug. The next time Windows 2000 Pro booted up, it noticed the second monitor and asked me to configure it. Basically, Windows wants to know where it is physically located (left, right, top, bottom) and what resolution it should have.
 
I suggest you give that some thought. My normal configuration is stock market windows on the right (original) screen, and browsers, etc. on the left screen. I use a Zone Alarm firewall. I have it set so programs that want to use the internet have to ask permission of me. "Permission" is granted in a pop-up window in the lower-right corner of the right screen. If I had thought more about it, I would have located that in the lower-right corner of the left monitor -- in the middle of the extended desktop, reducing mouse travel. (Yeah, I could change it. Yeah, I'm lazy. )
 
All is not roses with two monitors. This computer also boots SuSE Linux 10.1. SuSE was installed with just one monitor. Now, when it boots up, it recognizes the second monitor, but it doesn't really understand what to do with it. The initial bootup splash screen comes up on both monitors, but when it brings up X-Windows for the desktop, the second monitor goes blank except for the message: OUT OF RANGE, meaning that SuSE has told the video card to use a higher frequency than the monitor can support. It is presumably using the (higher) specs for the original monitor.
 
There are some more cautions if you are using Linux and an older monitor, or a basic video card. About 8 years ago, I fried a monitor running SuSE (about version 6, as I recall). Older monitors may not check whether they are being overdriven, and Windows is better than Linux was at avoiding the problem. An overdriven monitor can literally melt the electronic components in the drive circuits.
 
More recently, I fried a video card using a Linux screen saver. SuSE has (or at least had) a Matrix screensaver, which did an excellent imitation of the computer screens you saw in the movie. I liked it so much that I left it up on this computer. After about a month of that, the text on the monitor started getting "jumpy." I finally realized that the vector graphics in that "screen-saver" were driving the video card so hard that it began to fail.

I am working with a system integrator to put together a machine for heavy use of virtualization. He has put together lots of desktop and server systems with multiple monitors. His comment is that it is much better to get a single video card with multple monitor support, instead of adding another video card to a system that already has video support.

The problem with multiple video cards is that each makes heavy use of interrupts, and there is the potential for many conflicts at the system level.

That said, it appears that some careful shopping is appropriate. NexTag currently lists a Matrox G200 MMS Quad VGA/TV Tuner for only $119, but the description has a raft of strikeouts, and Matrox does not currently list it. A current offering is G450x4 MMS, which NexTag has for $449.

There appear to be 3 markets for 4x video cards: financial, server-workstations and gaming. Before selecting such a card, you need to decide how much speed, resolution and 3D multithreading capability you need, because the fancy cards get expensive fast.