Settings and optimization
You have two types of settings, the ingame and the client settings.
The client settings are available once you login on the Settings tab
Lag compensation improves smoothness during lag spikes at the cost of fps and the game could crash.
Matchview stretches the view of the field, lower matchview - longer pitch so the ball seems slower, mostly used by defenders (60%), normal is 80%, here’s a comparison picture
The match view settings tab it mostly graphics related, and lets you hide the referees or change the radar settings.
In the players tab you can control the team you join, turn on or off Default team colors, for when the teams have similar kits and toggle full screen.
And the ingame settings which are accessible once you join a game. (Pressing ESC)
The controls settings is the key configuration and the slow-moving range option.
Match chat settings will let you change the colors of the chat if you prefer, and let’s you manage the players you have in your ignore list.
Screen resolution can impact the game's performance and looks a lot. For example the game will run with better framerate on a 1024x768 resolution, rather than a high 1920x1080.
You can enter fullscreen inside a match window with the F11 key. You can also check the fullscreened matches box in Settings to start all match windows in full screen. Note that fullscreen matches may decrease framerate and cause lags.
SOUNDS may cause lag, if you are having performance issues try disabling sounds in game
You can use a chat command /ping in a match do see your current ping. Ideal ping is usually between 5-50, but of course the game is very playable with a ping up to 150. (The /ping command doesn't work in spectator mode).
You can also try to use "Standalone Legacy MatchView" option to improve the Framerate
An important tip to help on optimization is to change screen resolution, to have that SMOOTH feeling while playing, some people noticed 1366x768 worked, you might want to change and try out and see what fits best
Some settings that help players not have that "jittering" pixel feeling is the Smooth Transform + Antialiasing enabled.