Roblox Performance Optimization

Quick Reference

StreamingEnabled

Enable for large worlds — engine sends only nearby parts to the client.

-- Studio: Workspace > StreamingEnabled = true
workspace.StreamingEnabled = true
workspace.StreamingMinRadius = 64
workspace.StreamingTargetRadius = 128

• Parts outside the radius are nil on the client — always guard with if part then.
• Set Model.LevelOfDetail = Disabled on models that must always be present.
• Pre-stream an area before a cutscene or teleport:

workspace:RequestStreamAroundAsync(targetPosition, 5) -- 5s timeout

Hot-Path Loop Optimization

RunService.Heartbeat and RenderStepped fire every frame (~60×/sec). Keep them lean.

Bad — searching the hierarchy every frame

RunService.Heartbeat:Connect(function()
    local char = workspace:FindFirstChild(player.Name)
    local humanoid = char and char:FindFirstChild("Humanoid")
    if humanoid then humanoid.WalkSpeed = 16 end
end)

Good — cache references once, do work only when needed

local humanoid = nil

Players.LocalPlayer.CharacterAdded:Connect(function(char)
    humanoid = char:WaitForChild("Humanoid")
end)

RunService.Heartbeat:Connect(function(dt)
    if not humanoid then return end
    humanoid.WalkSpeed = 16  -- cached reference, no search
end)

Rules:

• Cache game:GetService() and part references outside the loop.
• Never call FindFirstChild, GetChildren, or GetDescendants inside Heartbeat.
• Throttle work that doesn't need every frame:

local TICK_INTERVAL = 0.5
local elapsed = 0

RunService.Heartbeat:Connect(function(dt)
    elapsed += dt
    if elapsed < TICK_INTERVAL then return end
    elapsed = 0
    -- expensive work here, runs 2×/sec instead of 60×/sec
end)

task Library vs Legacy Scheduler

Always use task — wait() and spawn() throttle under load and are deprecated.

Object Pooling

Reuse instances instead of creating and destroying them every frame.

-- ObjectPool ModuleScript
local ObjectPool = {}
ObjectPool.__index = ObjectPool

function ObjectPool.new(template, initialSize)
    local self = setmetatable({ _template = template, _available = {} }, ObjectPool)
    for i = 1, initialSize do
        local obj = template:Clone()
        obj.Parent = nil
        table.insert(self._available, obj)
    end
    return self
end

function ObjectPool:Get(parent)
    local obj = table.remove(self._available) or self._template:Clone()
    obj.Parent = parent
    return obj
end

function ObjectPool:Return(obj)
    obj.Parent = nil
    table.insert(self._available, obj)
end

return ObjectPool

-- Usage
local pool = ObjectPool.new(ReplicatedStorage.Bullet, 20)

local function fireBullet(origin)
    local bullet = pool:Get(workspace)
    bullet.CFrame = CFrame.new(origin)
    task.delay(3, function() pool:Return(bullet) end)
end

Level of Detail (LOD)

Built-in: Set Model.LevelOfDetail = Automatic — engine merges distant parts into an imposter mesh automatically.

Manual distance-based LOD:

-- LocalScript
local INTERVAL = 0.2
local LOD_DISTANCE = 150
local elapsed = 0

RunService.Heartbeat:Connect(function(dt)
    elapsed += dt
    if elapsed < INTERVAL then return end
    elapsed = 0

    local dist = (workspace.CurrentCamera.CFrame.Position - model.PrimaryPart.Position).Magnitude
    local visible = dist < LOD_DISTANCE
    for _, v in model:GetDescendants() do
        if v:IsA("BasePart") then
            v.LocalTransparencyModifier = visible and 0 or 1
        end
    end
end)

Reducing Draw Calls

• Merge parts that share a material into one MeshPart (export from Blender as .fbx).
• MeshParts batch better than CSG Unions (Unions re-triangulate at runtime).
• Reuse materials — 10 parts sharing SmoothPlastic costs far less than 10 unique textures.
• Use TextureId on a single MeshPart instead of stacking Decals on many parts.

Profiling with MicroProfiler

1. Press Ctrl+F6 in-game to open MicroProfiler.
2. Press Ctrl+P to pause and inspect a single frame.
3. Look for wide bars in heartbeatSignal (Lua), physicsStepped (physics), or render (GPU).
4. Label your own code:

RunService.Heartbeat:Connect(function()
    debug.profilebegin("MySystem")
    -- your code
    debug.profileend()
end)

Common FPS Killers

Common Mistakes