All source servers operate with something called the “tickrate”, which is a term you’ll hear a lot in the hosting world - but don’t worry, we’ll explain it for you.
The tickrate defines how fast the server will update each entities location ( An entity is a player, door, prop, etc. ) and how fast the server will check what each player is currently doing.
So the faster the tickrate, the more “real-time” the server is, the more accurate player positions are.
Faster tickrates are favoured on games like CS:GO where accuracy is important.
All their servers operate by default on a base tickrate of 66, while some run it at 128 on games like CS:GO to make the server more accurate.
In games like Garry’s Mod generally, the accuracy of the server isn’t as important as performance.
We personally found from experience operating on a tickrate of 16 will work well with about 70-100 players.
The tickrate can be set in your start-up parameters: