I have Asus AC 58 router. My speeds are 70mbps download 50mbps up. I made my old dlink router as a range extender on top floor. But when i connect to that one, the speed falls to 15mbps average download and 13 mbps average upload INSPITE of the fact that both routers are connected by cable (hence not wireless range extender). Is this speed drop normal even on wired range extender or i am doing something wrong?