This might be an issue with your output.
What specs do you have? Motherboard, GPU, Monitor type, -connected to it via which channel?
If you use an older motherboard with modern gear (e.g. something new-ish, like ultra-widescreens, new NVIDIA graphics cards, which haven't existed back then) you might have issues with that after all.
Doesn't matter if you have a high-end GPU. The motherboard must be able sorting incoming informations through a channel (HDMI, DVI, etc.) and if it fails to recreate that signal properly, it will output a corrupt/incorrect pixel ratio/resolution.
For instance, an older mainboard generation from year 2000 with a 1060 GTX and a modern monitor, which offers up to a 1080p resolution, won't display a correct 1920x1080 pixel resolution at all.