Server Tick Rate Explained

Server tick rate is the number of times per second a game server updates the game state. In shooters, this means 64- or 128-times-per-second updates to player positions, shots, and other actions.

Why Tick Rate Exists

In CS:GO and prior versions, a game server sent state updates to each client at the server's tick rate. The server's tick rate was thus a major factor in the smoothness and accuracy of a competitive shooter's feel.

Valve's documentation spelled out how Source tick rate works. The default tick rate in Source games was 66 (64 in CS:GO matchmaking), and the documentation warned that changing it could break mod code. Shots and peeks were timed to the cadence of ticks.

In practice, this meant that player actions were processed at the tick rate. Between ticks, motion and input could be queued up and then resolved at the next update.

While server tick rates were mostly lower in the past, some competitive games used 128 tick servers to give even more frequent server updates. Server tick rates also factored into the final hit registration in the shooters of the past.

Why Players Cares About Tick Rate

128 tick servers beat 64 tick because actions were processed twice as many times per second. The shorter time windows meant less time between updates for actions like peeking around a corner. The difference was felt through the pace and responsiveness of server updates, by analogy to going from 30fps to 60fps or 60fps to 120fps.

The shorter time between each server update would mean that all player input was sent to the server more frequently. Clients could display action and movement more smoothly, which could theoretically improve timing precision. The advantage especially mattered for competitive play because it allowed the game to give more frequent state updates, making the game feel smoother and more responsive to those playing.

What is the difference in CS2?

Valve's CS2 introduced a system that makes per-tick timing smaller. It's called sub-tick. With sub-tick, rather than forcing players to wait for an entire tick to pass for action resolution, the system records a timestamp for every input and processes them as smaller time windows within the tick.

In CS2, sub-tick changes what tick rate means for the game. Rather than a single tick servicing all indicators, sub-tick involves more frequent input recording, with timestamped action resolution within each beat.

Unlike a traditional 128 tick server, however, CS2 is not clocking server updates at a higher rate. In CS2, live matchmaking servers update at 64 Hz. The CS2 differences are at the input timing level, not at the overall rate of state updates from the server.

The difference in practical play is not as clear-cut as it used to be. There is less of a difference between servers labelled 64 and 128 tick. Server tick rate is less meaningul as a proxy.

Why Higher Tick Rates Cost More

Tick rate comes with a cost, which servers have to bear. Higher tick rates mean more frequent state updates, which require more server resources. When a server hosts more updates per second, it is doing more work each second.

The reason for this is that the number of network packets and server calculations scales up linearly with tick rate. A 128 tick server is going to have additional updates for each player in a game, compared to 64. Because the updates are handled server side, this means that the server runs twice as many simulation steps and can send up to twice as many updates per second. This increase in work requires more powerful hardware to handle.

What Should Players Know?

The key takeaways for competitive shooters:

• Server tick rate is a pacing factor for how frequently game state updates.
• Motions and player inputs are queued, and regular timing is determined per tick.
• 128 tick servers provide a faster game cadence, which is used in some competitive scenarios.
• In CS2, per-tick timing is smaller thanks to sub-tick, narrowing the gap tick rate used to create.
• Server tick rate and cost are interlinked, as higher rates mean more frequent state updates.
• In CS2, 128 tick is no longer the dividing line it was in CS:GO, as official servers run at 64 tick and rely on sub-tick instead.
• The idea that 128 tick servers allow for higher accuracy or faster game states is less relevant due to sub-tick.
• In CS:GO, players could tweak `cl_updaterate` and `cl_interp_ratio` within limits set by server-side variables such as `sv_minupdaterate` and `sv_maxupdaterate`; CS2 handles most of these networking settings automatically.