Is there any fix for the lag in PathfindingService?

When i use PathfindingService, the NPC dosent even reach me even when his walkspeed is bigger than 16.

This is the GIF: https://gyazo.com/13a5b3c2a759e4218b59c906db1a67c9

and heres the full chasing script:

function chase()

while true do

if not walking then

for i,v in pairs(workspace:GetChildren()) do

if not v:findFirstChild("Zombie AI") and v:findFirstChildOfClass("Humanoid") and v:findFirstChild("Head") then

if (v:findFirstChild("Head").Position - npc.Head.Position).magnitude < sight then

canrandomwalk = false

local thehumanoid = v:findFirstChildOfClass("Humanoid")

while (v:findFirstChild("Head").Position - npc.Head.Position).magnitude < sight and thehumanoid.Health > 0 do

npchumanoid.WalkSpeed = 17

local path = game:GetService("PathfindingService"):ComputeRawPathAsync(torso.Position, v:findFirstChild("Head").Position, 200) --find the path from scp's torso to victims head

local waypoints = path:GetWaypoints() --get the every point of the path

local heartbeat = game:GetService('RunService').Heartbeat

local pointnumber = 0

if path.Status == Enum.PathStatus.Success then

for q,w in pairs(waypoints) do --for every point existing..

local allow = 0

npchumanoid:MoveTo(w.Position) --...walk to the point

while (torso.Position - w.Position).magnitude > 4 and allow < 25 do

allow = allow + 1

heartbeat:wait()

end

if w.Action == Enum.PathWaypointAction.Jump then

npchumanoid.Jump = true

end

npchumanoid.WalkToPoint = v:findFirstChild("Head").Position

end

end

end

else

canrandomwalk = true

end

end

end

end

wait()

end

end