Whats the more efficient way of having 100's of conveyors?

Making a cart game, going to have many many conveyors with multiple speeds.

Would it be better this way in each conveyor block,

while wait(0.1) do
    script.Parent.Velocity = script.Parent.CFrame.lookVector * script.Parent.Speed.Value
end

Or do something like

while wait(0.1) do
    for i,v in pairs(workspace.Conveyors:GetChildren()) do
        if v.Name == "slowConveyor" then
            v.Velocity = v.CFrame.lookVector * 16
        elseif v.Name == "mediumConveyor" then
            v.Velocity = v.CFrame.lookvector * 30
        end
    end
end

The second one was just coded here, so if there's any errors I apologize.