This tutorial will allow you to use resolutions that aren't normally available to you, while letting your video card do the upscaling work so that your monitor doesn't have to, which results in better quality and a correct aspect ratio. It assumes a number of things, and this may not work if any of these are not the case:
You have a Geforce card, series 6 or better.
You have the Forceware drivers from nVidia.
You are using a widescreen LCD monitor via digital DVI.
Also, this tutorial may not work equally well for all resolutions. Here are some guidelines to increase the chances that your resolution will work right.
Neither resolution number (horizontal or vertical) should be greater than your monitor's maximum res.
The horizontal resolution number should not be below 800, and the vertical resolution number should not be below 600.
Both resolution numbers should be divisible by 4.
Personally, I recommend sticking with resolutions that can be found on other monitors (except for 1366x768 - use 1360x768 instead). But it is possible to use some really weird resolutions too. For the example, I am going to add 1068x600, a 16:9 resolution, to my monitor which has a native res of 1280x768, a 15:9 resolution. It will scale correctly and have the right amount of black bars.
First, open the nVidia Control Panel. Make sure that "Advanced View" is turned on. Go to Display->Appearance->Manage Custom Timings. You should get a menu that looks something like this, except your "Custom timings" box is probably empty.
If you have multiple monitors, select the monitor you want to add the resolution to, and click "Create."
In the next series of pictures, I have circled some fields. A red circle means "use this value." A blue circle means "use your own value." No circle means "leave it at whatever it defaults to."
After you click "Create," you'll get this menu (you may have to go through a disclaimer first):
Set the top two boxes to set your custom resolution. Refresh rate should be 60, Bits per pixel should be 32, and Interlaced should be off. Now click "Advanced." You'll get this:
Leave the back-end parameters alone for now. At the bottom, set the "Scaling type" to "Adapter." Set the bottom two boxes to your custom resolution, same as the top two boxes. Once that's done, look at the back-end parameters and set "Timing standard" to "Manual." You will get this:
Most of the settings should already be correct. Both sync polarities should be negative. If either one defaults to positive, change it. Also make sure that refresh rate is 60 and that your active horizontal pixels and active vertical lines are correct. Leave everything else the way it is.
Now click "Test." If all goes well, nothing will appear to happen, but it will report success. OK your way out.
Now, test your resolution. I recommend doing it from within the nVidia control panel in case something goes wrong. Go to "Change resolution attributes," and slide the resolution slider back until you hit your resolution. Now click "Apply." If the screen appears garbled or distorted, press Esc immediately. This resolution didn't work so well. But if you're lucky, it will work. In my case, it did, and my screen looked like this:
A note about the black bars: They do appear on my screen, but they do not show up in screenshots - a screenshot will come out at 1068x600 resolution without any black bars. I added them manually to show what it looks like on the screen. What this means for you is that if you have a 16:10 monitor and you add a 16:9 resolution this way (like 1280x720), you will see black bars on your monitor, but not on your screenshots.
Anyway, these black bars will only appear if your custom resolution has a larger aspect ratio than your native res. If it has a smaller aspect ratio, you'll get black bars on the left and right. If it has the exact same aspect ratio (such as 1680x1050 on a 1920x1200 monitor), you'll get no black bars at all.
