Having a Issue with NPC Attack Script, Recv is high ingame?

I understand what I'm doing wrong and why it's high in Recv but I don't know how to get around this issue or how to fix it. There is around 20 NPC's on the map with this Script.

--EDIT-- The Script Checks if the player is within Range and Attacks the player and put's a Sound of the NPC hitting them but this Checks all the time and it's making the game lag when there's a lot of NPC's. The Line of code that I figure out that was making this issue is this..

local Players = game.Players:GetPlayers() for i,Player in ipairs (Players) do local char = Player.Character local Plr = Player if char ~= nil then local hum = char:FindFirstChild("Humanoid") if char.UpperTorso ~= nil then local Plu = char.UpperTorso

With this it's checking all Players ingame all the time and Rising the Recv end to 100-1000ms, This is what I'm trying to get help with, I like to know if there's a diff way to go around using that so I can check if the player is within Range or not but not have it run a 100 times within a second. There's no errors with the script.

`local NPC = script.Parent.Parent local Humanoid = NPC:WaitForChild('Zombie') repeat wait() until script.Parent.Parent.Torso local Damage = game.ReplicatedStorage.BoarConfigs.BoarDamage.Value

local COOLDOWN = 3 local h = false

while wait() do

local Players = game.Players:GetPlayers()
for i,Player in ipairs (Players) do
    local char = Player.Character
    local Plr = Player
    if char ~= nil then
    local hum = char:FindFirstChild("Humanoid")
    if char.UpperTorso ~= nil then
        local Plu = char.UpperTorso
        local m = (script.Parent.Parent.HumanoidRootPart.Position - Plu.Position).magnitude
        if m <=6 then
        if h == false and hum.Health >0 then
        if Plu ~= nil then  
    local Def = char.Def
    local SDef = char.SDef
    local MainDef = Def.Value + SDef.Value
    local NewDamage = Damage - MainDef

    local asound = Instance.new("Sound", char.Head)
        asound.SoundId = "http://www.roblox.com/asset/?id=367499850"
        asound.Name = "MobAttack"
        asound.Volume = 0.3
        asound.PlaybackSpeed = 0.3
        asound:Play()
        hum.Health = hum.Health - NewDamage
        Humanoid.WalkSpeed = 13
        h = true
        wait(COOLDOWN)
        char.Head.MobAttack:Destroy()
        Humanoid.WalkSpeed = 16
        h = false
    else
        print("Player has left the game or isn't in Range")
        end
        end
end
end
    end
    end
end`

If anyone can give me a hint on a way around this or let me know how too would be great.