FiveM resmon high ms: how to find and fix slow scripts

You open the resource monitor and one script shows this:

my_script        0.35 ms

An idle script should be near zero. A script that eats a third of a millisecond, or much more, on every frame makes your game stutter, and the players with weaker computers feel it first. This guide shows how to see which resource is the problem and the changes that bring it down.

#Open the resource monitor

In the F8 console of the game, type:

resmon 1

An overlay shows every client resource with its CPU time (ms) per frame and its memory. Type resmon 0 to close it. Check these things:

• Stand still, in a quiet place, and read the list. The numbers that matter are the ones that stay high when you do nothing.
• Look at who is at the top. A resource that goes up only near its own marker or shop is normal. One that is high everywhere is not.
• Watch it a few seconds. A single peak when a script starts is harmless; a constant value is the problem.

The ms is time on the client. Server performance is a separate topic: see server thread hitch warning.

#Cause 1: a loop with Wait(0)

The most common reason for a high value is a loop that runs every frame, all the time:

CreateThread(function()
    while true do
        Wait(0)
        local ped = PlayerPedId()
        local coords = GetEntityCoords(ped)
        local dist = #(coords - vec3(215.0, -810.0, 30.7))
        if dist < 3.0 then
            DrawText3D(215.0, -810.0, 30.7, 'Press E')
        end
    end
end)

This runs the natives 60 times a second, even when the player is on the other side of the map. Most of the time the answer is "nothing to do", and that cost is wasted.

#Fix 1: sleep when you are far away

Let the loop sleep longer when nothing is close, and only run every frame when the player is near:

CreateThread(function()
    local target = vec3(215.0, -810.0, 30.7)
    while true do
        local sleep = 1000
        local coords = GetEntityCoords(PlayerPedId())
        local dist = #(coords - target)

        if dist < 10.0 then
            sleep = 0
            if dist < 3.0 then
                DrawText3D(target.x, target.y, target.z, 'Press E')
            end
        elseif dist < 50.0 then
            sleep = 250
        end

        Wait(sleep)
    end
end)

The loop checks once per second when you are far away, which costs almost nothing, and runs every frame only inside the 10 metre area where it draws. Use #(a - b) with vec3 values for the distance: it is faster than the older GetDistanceBetweenCoords native.

#Fix 2: cache values you reuse

Calling a native every frame to get a value that rarely changes is a waste. PlayerPedId() is the classic one. Store it once and refresh it only when it can change:

local ped = PlayerPedId()

CreateThread(function()
    while true do
        Wait(500)
        ped = PlayerPedId()
    end
end)

If you use ox_lib, it does this for you. cache.ped is kept up to date, and cache.vehicle and cache.serverId work the same way:

local coords = GetEntityCoords(cache.ped)

lib.onCache lets you react when a cached value changes, without checking in a loop.

#Fix 3: stop calling natives every frame

Check the body of the loop and ask for each line: does this really have to run every frame? Move out what does not.

• Drawing (text, markers, sprites) has to run every frame, but only while it is visible.
• Reading data (job, money, inventory) does not: read it on an event, and keep it in a variable.
• Searching (GetClosestVehicle, GetGamePool, loops over all players) is expensive. Run it once every second or two, not every frame.
• Do not create things in a loop: creating blips, text entries or tables every frame fills memory and makes the garbage collector work.

-- run once per second
local closest = nil
CreateThread(function()
    while true do
        closest = GetClosestVehicle(GetEntityCoords(cache.ped), 5.0, 0, 70)
        Wait(1000)
    end
end)

#Fix 4: use ox_lib points and zones instead of loops

Most "am I near this spot" loops are not needed. ox_lib can do the distance work for you, and only runs your code when it matters.

A point calls a function when you enter or leave a radius, and one every frame only while you are inside:

local point = lib.points.new({
    coords = vec3(215.0, -810.0, 30.7),
    distance = 10.0,
})

function point:onEnter()
    print('entered')
end

function point:onExit()
    print('left')
end

function point:nearby()
    DrawText3D(self.coords.x, self.coords.y, self.coords.z, 'Press E')
    if self.currentDistance < 2.0 and IsControlJustReleased(0, 38) then
        print('used')
    end
end

Zones do the same for shapes such as a sphere, a box or a polygon:

local zone = lib.zones.sphere({
    coords = vec3(215.0, -810.0, 30.7),
    radius = 3.0,
    onEnter = function() print('in') end,
    onExit = function() print('out') end,
})

For interaction with entities and spots, a target resource (ox_target, for example) replaces the "press E" loop in the same way. Check the ox_lib documentation for the exact options of each.

#Check the result

Run resmon 1 again. A fixed script should sit near 0.00 ms when you stand away from its spots, and rise only when you are near them. If it is still high, look for a second loop in the same resource: one Wait(0) is often not the only one.

Warning: do not set a long sleep in a loop that handles a key press or a drawing. If you sleep 500 ms and the player presses the key, the script will miss it. Sleep only when you know nothing is going on, and drop to Wait(0) when something is.

#Checklist