You can make most PC games look great with the right graphics tweaks. But if you really want to get down and dirty—and have the graphics card to handle it—you can actually run your games at a higher resolution than your monitor supports (sort of). The folks at LinusTechTips explain how.
This "trick" is really the usage of a lesser-known type of anti-aliasing, called Ordered Grid Super Sampling Anti-Aliasing. Unlike regular anti-aliasing, which just smoothes out the edges of your game's graphics, OGSSAA basically sends a higher-than-native resolution signal to your monitor, and then downsamples it to your monitor's native resolution for a sharper image all around. LinusTechTips forum user tabuburn explains it well:
[For example,] Your display is natively able to support a resolution up to 1920x1080. Using Downsampling it will send out a signal to tell your display to output a resolution of 2560x1440. Now on a display that can output a maximum resolution of 1080p has about 2 million pixels while a 1440p display outputs 3.7 million. Downsampling does not increase the amount of pixels being displayed. It can't go beyond that. What it does is bring that 1440p resolution to your 1080p display and compresses it to fit inside the screen. The effect it has is similar to zooming out on a lower resolution picture.
Of course, this has downsides. It's very inefficient and will decrease performance quite a bit, and many consider it similar to overclocking—so it carries some risk of damage as well (at least in theory). This isn't one of those settings you would use for all your games, but it could be useful for some crappy console ports, or games without adequate settings. It's also not for the faint of heart, but it's a pretty interesting little experiment. Check out the video above for information on what hardware it works on, its upsides and downsides, and the full instructions.
How to Run Higher Than the Maximum Resolutions on Your Display | LinusTechTips Forum
Improve Visual Quality by Running your Monitor at a Non-Native Resolution | LinusTechTips on YouTube