Always check "GPU scaling" before creating a custom res. If your monitor fights the new resolution, let the graphics card handle the heavy lifting. Your monitor won't know the difference, but your frame rate will.
Here’s the trick: You render the game at 4K (3840x2160) but tell your 1080p monitor to display it. The GPU crunches the math, squishes those extra pixels into your screen, and the result is astonishing. Jagged edges vanish. Textures look richer. It is essentially the most expensive, brute-force form of anti-aliasing available. custom resolution
Whether you are trying to squeeze an extra 20 Frames Per Second (FPS) out of an aging graphics card or force an ultrawide aspect ratio onto a standard laptop screen, creating a custom resolution is the art of telling your monitor, "Not today, default settings." The most common use for a custom resolution is actually a step backward. It’s called Downsampling (or Dynamic Super Resolution in NVIDIA speak, Virtual Super Resolution for AMD). Always check "GPU scaling" before creating a custom res