helixx :
Ajbboy123 :
helixx :
It will not mess up your monitor whatsoever, but may mess up the game.
How would it mess up the game?
It may have black lines if the aspect ratio is screwed up or if the resolution is too small, it may cut some things out. However that can be easily adjusted by changing the resolution.
720p and 1080p are both 16:9, so there will not be any letterboxing, and it shouldn't cut anything off.
You're not going to cause any harm to your hardware by playing at 720p, but man, that's going to look terrible. This should be pretty much your last recourse for playability, after exhausting pretty much every other option to improve performance. Bare minimum settings at 1080p would be a better choice, if you haven't already tried it.