When you teleport into a town packed with players, the server has to send the appearance, gear, and status of hundreds of newly visible players all at once.
Why You suddenly appear somewhere crowded by teleporting, logging in, or switching channels → Effect Full data for hundreds of players is built and sent at once, and your PC also loads it all at once → On screen A brief pause right after arrival, characters pop in late one by one, and input lags
While moving or changing zones, Right after login or maintenance
Owner
Primary owner Game team (Server development) · Also Game team (Client development)
Game team action items
Server: send in order of distance, spread over several ticks, cache appearance data. Client: preload during the loading screen, create received characters over several frames.
Ballpark numbers
If one player’s appearance, gear, and buff data is 300 bytes, 500 players come to about 150 KB. Tens of times the usual per-tick traffic (a few KB) arrives in a single moment.
On the graph
Surge after opening · Bytes sent per connection, client frame time
Where to look
Bytes and packets sent over that connection in the first few seconds after arriving somewhere crowded (server log), and client frame time (net graph, client log)
Confirmed if
Right after arrival, outbound traffic on that connection shoots up to tens of times a normal tick and then settles, and client frame time spikes at the same moment
Ruled out if
The same pause when moving somewhere quiet: points to a zone transfer (handoff between servers) or client loading
Check with
Game server or client logs and metrics
Sources
Detailed Actor Replication Flow in Unreal EngineEpic Games When an actor channel is first opened, initial data such as position and rotation is sent along with it, and once the connection is saturated, the remaining actors wait for the next tick
Actor Priority in Unreal EngineEpic Games Actors are prioritized by distance and view direction, and the nearest visible ones are sent first