The game it's self has not any performant graphics on it i've worked for me very well since an AMD 2.1 computer 4 years go

1.The important thing is the connection between you and Server its self
2.New intense colored armors can be on the old PC a problem.
3.Using to many in a single place the lapisia smoke on weps can affect lagging
4.Maps is not a really issue because the client is loading only the map your on, is not keep loading everything in game at a time.
This is an result of opened 20 game.exe and still left enough memory left for 10 more bcuz the important thing is the connection i use an 1GB fiber link