Distance from the router, as well as floors, walls, and large metal objects between a device and the router can interfere with wireless connectivity. Piggybacking, if you fail to secure your wireless network, anyone with a wireless-enabled computer in range of your access point can use your connection. Network congestion, Routers or other network equipment are overloaded with too much traffic. Speed Mismatch. This occurs when multiple users try to make use of the same server. I could go on and on.
5,400 because it turns at the right speed, but if it is too fast or too slow, it will not perform at it's fullest potential. Such as speed and storage.