I have been told that the shorter the cable the better, and have been advised to use a Ethernet Cable instead.
The shorter the cable from the socket to the router box the better, but sometimes it just isn't practical where it is, I moved mine to give a better wireless signal.
If is from the socket on the wall to the router, it's satellite cable with F type connectors, screw them in firmly but not over tight.
From the router to the PC use Ethernet RJ45 cable.
You will get a slight loss the greater the distance, but we are talking milliseconds, and it's still faster than using wireless.