Seeing Double - Using Two Monitors at Once

Two displays, one computer.

Can you do it? Sure you can. Windows XP supports multi-monitor configurations in a couple of different ways. You can either have a video card with more than one output (sometimes called a multi-head video card) or you can install two video cards. I've tried both of these configurations and either one is great.

Two video cards, two monitors

The first time I set it up, I used left over parts from my old computer. I had an old 14 inch monitor that could only go up to 800x600 resolution which I connected to an old PCI S3 video card with only 2MB of RAM. The monitor that I prefer to look at is a 19 inch screen connected to a 32MB AGP NVidia GeForce3 card. The key to this set up is that there is one PCI video card and one AGP video card. In order to get Windows XP to recognize and use both, I had to set an option in my BIOS that told it that the primary VGA BIOS is the one on the PCI video card. I believe this is because the computer's BIOS must have a single display to output to when the computer is starting up. Once Windows takes over it isn't important, I used the other video card more since it was connected to the larger display. After setting the primary VGA BIOS, I had to tell Windows to use the monitor as well. That was pretty easy. After Windows starts, just right-click on the desktop and pick "Properties." In the "Display Properties" dialog, pick the "Settings" tab. Then you should see two large boxes numbered "1" and "2" which represent your two displays. The second display may appear greyed out. To enable it, you have to check the box marked "Extend my Windows desktop onto this monitor." After that you can adjust settings for both displays. Click the "OK" button and you should get your desktop extended across both screens.

Display Properties

One video card, two monitors

I enjoyed that set up for quite a while (maybe a whole year), but the smaller monitor wasn't as useful as the large one. It was great for a little chat window or my winamp playlist. The problem was really that my primary video card (the GeForce 3) wasn't keeping up with modern games. I picked up a GeForce FX 5200 just recently and a refurbished 19 inch monitor. This video card has two outputs - one VGA and one DVI. Not all cards that have both outputs can use them both at the same time, so check the box before you buy the card. Another important detail for me was that it had to include the DVI to VGA adapter with the card, otherwise I'd have to pay a couple more dollars for that. I don't doubt that in a couple of years, a VGA to DVI adapter will be more desirable, but today both my monitors only have a VGA connector.

So to set this new hardware up, I had to go into my BIOS and set it to use the AGP card as the primary. Next I pulled out the old PCI VGA card and the GeForce 3 AGP card. I installed the new video card and plugged in the DVI to VGA adapter. Then I plugged in both 19 inch monitors. I powered it up and let Windows figure out the hardware changes. You may want to take smaller steps than I did so that Windows only has to detect one change at a time. In the end, I had to right click the desktop and choose "Properties" then go to the "Settings" tab. I checked the "Extend my Windows desktop onto this monitor" for the new monitor and voilá. One difference with a dual head video card instead of two separate cards is that there are more options for how to handle the two screens. To get to these options, click the "Advanced" button on the "Settings" tab of the "Display Properties" dialog. I have an extra tab labelled "GeForce FX 5200" but I'm sure ATI has a similar addition for their video cards. I tried out the choices they give for handling both monitors as one display, but I found that I preferred the default set up. The only way to decide for yourself is to experiment.

I find lately that the single 19 inch display I have at work is becoming inadequate. I want to see all of two Excel spreadsheets, or copy data from one full screen application to another. With two displays this is a perfectly normal and simple thing. Most of the time I find that I can keep a few chat windows open on the right side display while I work in one maximized window directly in front of me. Other ways it can be useful are when you have a web browser open to some reference material that you're looking back to over and over. Sure you can alt-tab back and forth, but why do all that extra work? You might even have room for that second monitor already. If you need a hand, give me a call and I'll be glad to take care of it in person, anywhere in and around Windsor.