I am not referring to input delay, but it lags

Vsync will probably solve your issue... but.. you're sacrificing FPS. Unless you're a sub 5 runner, I wouldn't worry about running at 60fps flat.

Activating VSync gives me input lag, which is really terrible, so I´m trying to see if I can do anything else... but thanks anyway. I get the lag when I´m not playing on fullscreen (so I can have livesplit comfortably). And yeah, I do care about fps, I´m going for high 4:57 and prob mid 4:57 eventually

Does Nestopia UE (http://0ldsk00l.ca/nestopia/) lag for you as well?

I tried Nestopia UE and yeah, it still lags I don´t know if it is my pc, this wasn´t happening some months ago. Not sure

It's like whenever there's something else happening on the screen that isn't from the emu itself, like for example, when the volume bar shows up, a windows notification, when I record, etc. It's weird. Does the emu have low priority or something like that?

it could be that. you could try to set nestopia to high priority and see if it solves the issue

Nope. I don´t know. Perhaps I should try other emus too