Nvidia provides a convenient way to set a custom resolution via its graphics control panel while including extra options like 'sync width'. For the most part, you should leave the exotic settings alone and just tweak the pixel resolution. However, if you're connecting to a really old TV, you might need to fiddle with parameters such as 'front porch', a timing setting (specifically, the time between when the last scan line displays and when the next sync pulse from the GPU arrives) used in analog video
Another display setting you should know how to tweak is the aspect ratio. Older games and standard-definition TV might run in a 4:3 aspect ratio, such as 640 by 480 pixels or 1024 by 768 pixels. When you play them on a modern widescreen monitor, they may look unnatural when stretched to match the full width of the display. GPU control panels have settings to let you tweak aspect ratio; and though some monitors have aspect ratio controls built-in, using the GPU control panel is simpler and ensures that your settings remain the same if you should ever switch displays.
To adjust the aspect ratio, open your GPU control panel and find the radio buttons that control this setting. The top button leaves the source materials' aspect ratio unchanged, but enlarges the image to use as much of the monitor space as possible (meaning that you'll probably have gray or black bars on either side of the image, if your source material is 4:3). This is the preferable setting.
Normally, the 'Scale image to full size' option is switched on by default, but you'll want to avoid this option if you're having scaling issues.
The third option--which Nvidia calls 'no scaling' and AMD refers to as 'use centered timings'--prevents the image from being scaled at all. If you try to display a 640 by 480 image on a 2560 by 1600 display with this setting enabled, you'll end up with a tiny picture at the center of your screen. Though this may represent the most accurate image possible, you probably won't find it a pleasing option.
Your graphics control panel has a few more-specific aspect ratio settings that you can tweak, but you can ignore these if you're using a widescreen monitor manufactured in the past five years.
Desktop color settings
The two types of color settings in GPU control panels are desktop color and video color. The latter term refers to color settings for video playback. The different panels exist due to differences in the way that PC graphics and video playback handle color. We'll discuss video color settings in more detail shortly, but first let's look at desktop color.
A single control panel handles desktop color settings for Nvidia-based graphics cards.