Custom Resolution Not Working

I know the launch options needed to set a specific resolution for Steam games, (-w #### -h ####), but no values I enter are working. I try to make the resolution 1920 x 1080, and every time I launch the game it’s just in my native resolution of 1280 x 1024. I’ve tried launching the game in both windowed and fullscreen mode, but to no avail. When I go into the Garry’s Mod options and change the aspect ratio to 16:9 - widescreen - and restart the game, it automatically goes back to 4:3.

I would greatly appreciate some insight on how to sort out this dilemma.

You can’t increase your resolution above your native resolution, get another monitor I guess

Okay, that makes a ton of sense. Thanks for the help!

Edit: I found a way around the problem; I set the window’s resolution to 960 x 540 - half of the desired resolution - and entered poster 3 into the console. Now, I can play in a tiny screen and still take screenshots 3x the quality!