Lag above 30 players

Hi, I have noticed that when servers get above 30 players they start to lag.

I was just wondering if there is a way around this.

I have tried setting rates.

The server specs are not the cause.

Your servers processor sucks.
I use Vilayer in realtime 64 slots and the ping is from 7 to 40 for everyone and no lag at all.

Vilayer…I CAN’T BREATHE!
/me dies

Aren’t source servers not guaranteed to run over 24 players?