Question regarding internal resolutions

Hi there,

If any of you have ever played Dark Souls, you'll know that without the DSFixer mod thingo, setting your resolution in the game settings would run the UI and all at that res (1080p for example), but the game engine itself would run at a much lower resolution no matter what you tried changing your res settings to.

I am wondering if it's possible to change the internal resolution of games manually. I believe this is the same "render quality" ish setting that Dota 2 and Guild Wars 2 utilize, essentially letting you lower your res without affecting the scaling and clarity of the UI. This would be super handy for lower-end rigs or laptops!

Any knowledge shared would be greatly appreciated.