Remote procedure calls in Unity - Performance & Optimization

Performance: Remote procedure calls

MEDIUM IMPACT

Remote procedure calls affect network latency and responsiveness in multiplayer or distributed Unity applications.

Sending frequent updates for player position in a multiplayer game

Unity

void Update() {
  if (Time.time - lastSent > 0.1f) {
    CmdSendPosition(transform.position);
    lastSent = Time.time;
  }
}

[Command]
void CmdSendPosition(Vector3 pos) {
  RpcUpdatePosition(pos);
}

[ClientRpc]
void RpcUpdatePosition(Vector3 pos) {
  transform.position = pos;
}

Limits RPC calls to 10 times per second, reducing network load.

📈 Performance GainReduces network traffic by 90%, improving responsiveness.

Sending frequent updates for player position in a multiplayer game

Unity

void Update() {
  CmdSendPosition(transform.position);
}

[Command]
void CmdSendPosition(Vector3 pos) {
  RpcUpdatePosition(pos);
}

[ClientRpc]
void RpcUpdatePosition(Vector3 pos) {
  transform.position = pos;
}

Sending RPC every frame causes excessive network traffic and delays.

📉 Performance CostTriggers high network latency and bandwidth usage, causing input lag.

Performance Comparison

Pattern	Network Calls	Latency Impact	Bandwidth Usage	Verdict
Send RPC every frame	High (60+ per second)	High latency and lag	High bandwidth usage	[X] Bad
Send RPC at fixed intervals	Low (10 per second)	Lower latency	Reduced bandwidth usage	[OK] Good

Rendering Pipeline

RPCs do not directly affect rendering but impact game responsiveness by delaying state updates across clients.

→Network Transmission

→Game State Update

→Rendering indirectly

⚠️ BottleneckNetwork Transmission latency

Optimization Tips

1Avoid sending RPCs every frame; use fixed intervals instead.

2Keep RPC payloads as small as possible to reduce bandwidth.

3Use Unity's Network Profiler to monitor and optimize RPC usage.

Performance Quiz - 3 Questions

What is the main performance issue with sending RPCs every frame in Unity multiplayer?

A It causes excessive network traffic and latency.

B It increases CPU usage on the client only.

C It reduces the frame rate of the local player.

D It causes memory leaks in the game.

DevTools: Network Profiler

How to check: Open Unity Profiler, select Network section, and monitor RPC call frequency and data size during gameplay.

What to look for: Look for high RPC call counts and large payloads causing spikes in network usage.