Borderless windowed mode:
https://www.reddit.com/r/StreetFighter/comments/46b7ym/pc_enable_borderless_window_mode_for_sfv_by/
No vsync input lag, no tearing, and you can freely multitask without worrying about the idiotic alt-tab problem mucking up the game for your opponent.
Now the only thing missing is to allow background inputs.
If you click out of the game (second monitor surfing/chatting/working or even gaming) the game will not input.
You have to click to the game again and it works fine here.
Now I have to decide between fullscreen 1440p downsampling or borderless 1080p.
Downsampling would win if i wouldn't do other stuff on the second monitor and a slight window switch minimizes the game and that's the reason why I don't do that often.
Games like MGS V are allowing background inputs.
If background inputs work with the game I can open Rocket League on the second monitor and we can both play simultaneously online!
I tried this via the .ini and it didn't seem to do anything, and when I did it via Steam launch options it did work but I got performance hiccups. Seems like a game that runs on current gen consoles shouldn't have an issue running on an i5 3750. Or could it be the GPU (970) that is the problem? Am I missing something obvious?
Nope, GTX 970 and your cpu are even ready for almost ultra/1440p.
I have a similar rig and it works fine here.
Just try to add ''-fullscreen -borderless'' in the launch options in steam for the game.