A lot of saf pvpers use Chromium based browsers (ie: Chrome, Opera, Torch etc) Sometimes play aqw on an exported swf.
The "edgy" people would use something Mozzila based, usually Maxthon, which I recommend people try out to dual screen aqw.
From my experience, the trick to get aqw less "laggy" is to reduce the amount of process running on your computer, close that windows media player that you have on for some reason or something (reduce cpu usage; aqw runs on flash).
So kinda depends on your hardware, whether if your cpu likes w/e browser you're using. You'd wanna play test browsers and see which uses up cpu usage. Dont be afraid to experiment.
You also wanna test how good your ping is with aqw
but yeah chrome works lol just dont play aqw with 30 tabs open
and honestly people shouldnt be lagging in 2016, unless you tell me you're still running that craptop running windowes vista from 2008 or if you tell me that your pc is made by fisher price smh