[CONTROLA]

onfoot_rate 40
incar_rate 40
weapon_rate 40
stream_distance 300.0
stream_rate 1000

^ I've got these values in server.cfg on a ~120 players server. Is it ok? Are these unusual values? Because the CPU Usage seems to get pretty high when having many players.

[Goldino]

What has this got to do with scripting?

[Babul]

those values are ok, they are close to the default values.
the CPU usage on high player counts are mostly script related, dont worry about the network usage yet.

i suggest you to use the performance profiler plugin, and let it run on your server. but ATTENTION! the plugin requires a LOT of memory, dont let it run for a long time: 10-15 minutes with 100 players should give you proper results.
let the profiler care for the gamemode only for the first attempt. if you dont get helpful results (like 1 or 2 functions eating a lot of cpu time), THEN its a filterscript, but i assume the gamemode causes the lag.
a (lot of) loop(s) consisting MAX_PLAYERS are the main reason for lag...