Electricians around here butcher everything, they are idiots. I consistently see them have cat5 in the wall and leave 3-4 inches of wire untwisted before terminating to the cheapest 'self-punch' keystones you can imagine. Same at other end.
When I test, I still get 980+Mbps from these trash connections.
You have to really f^ up a wire run and termination bad to cause a speed drop like you are talking - at least at those short distances.
When you get into 10Gbit networking, now you are talking needing perfect connections.

I would be looking at the equipment.
P.S. = I hate Netgear.