Roblox Performance

When to Load

Use when profiling, diagnosing lag, or setting performance budgets. For code-level micro-optimizations (pooling, throttling, relevance filtering, lazy loading) load roblox-luau-patterns; this skill measures and tunes the engine.

Quick Reference

Profiling Tools

• MicroProfiler (Ctrl+F6): Per-frame breakdown: scripts, physics, rendering. Primary tool for finding what's slow.
• Developer Console (F9): Stats tab: memory, network, render stats. Server Stats for server-side metrics.
• Script Profiler (Ctrl+Alt+F5): Per-script CPU and heap.
• Custom labels: debug.profilebegin/debug.profileend name hot regions in the MicroProfiler; debug.setmemorycategory names thread memory in the console. Gate behind a flag (full.md).

Performance Targets

"Expensive" means the profiler shows it on a hot frame path (raycasts, clones, large finds, replication-heavy writes). Throttle from measurements, not a universal number; re-profile after shipping. Micro-optimizations live in roblox-luau-patterns.

Parallel Luau

• Use Actors only after profiling identifies isolatable CPU work.
• Workers compute; synchronize before restricted DataModel writes.
• SharedTable and mutexes add coordination cost; they do not replace ownership boundaries.

Object Pooling

Pre-clone and reuse. Canonical pool code (token-lease ownership): roblox-luau-patterns.

StreamingEnabled Essentials

• On by default. Container-scoped: only Workspace descendants stream. ModelStreamingBehavior = Improved streams non-BasePart descendants with their parent Model; Legacy streams only BaseParts.
• Streamed-out = parented to nil, not destroyed. Luau refs persist if it streams back.
• Config (Studio): target defaults 1024, min 64; set StreamingIntegrityMode; tune from data.
• Gotcha: FindFirstChild("DistantPart") returns nil if streamed out. Use WaitForChild with timeout.

Mobile

• Profile geometry, textures, particles, UI, shadows on low-end devices.

Full reference with code examples and API tables: references/full.md