:BindToRenderStep causing major framerate drops?

I'm using RunService:BindToRenderStep to make a brick stay relative to the camera, and it works very well but it causes major framerate drops. Like 60 FPS to 25. For some reason, it happens only when you move the camera, and if I zoom out really far from the map, no more framerate drops. Here's the code. It's a module script, but I've tried it out of one and the same thing happened.

local module = {}
local cam = workspace.CurrentCamera
local rightSideOffset = CFrame.new(2,0,-2)
local rightSideRotation = CFrame.Angles(math.rad(90),math.rad(0),math.rad(35))
local runService = game:GetService("RunService")

module.InitiateHUD = function()
    local rightSide = Instance.new("Part", cam)
    rightSide.FormFactor = Enum.FormFactor.Custom
    rightSide.CFrame = cam.CoordinateFrame*rightSideOffset*rightSideRotation
    rightSide.Anchored = true
    rightSide.Transparency = 0.7
    rightSide.Material = Enum.Material.SmoothPlastic
    rightSide.TopSurface = Enum.SurfaceType.Smooth
    rightSide.TopSurface = Enum.SurfaceType.Smooth
    rightSide.Size = Vector3.new(1.5,0.2,3)
    rightSide.CanCollide = false
    runService:BindToRenderStep("positionRightSideHUD", Enum.RenderPriority.Character.Value, function() rightSide.CFrame = cam.CoordinateFrame*rightSideOffset*rightSideRotation end)
end



return module