After seeing that my wireless speeds were much faster than the speeds I was getting over Ethernet, I decided to invest in some new cables. I didn’t know it before, but I saw while I was changing them out that my current cables were Cat 5e. While putting my network together, I had just been grabbing whatever cables I could find in my scrap drawers. Now I have Cat 8 cables and my speeds jumped from 7MB/s to an average of over 40MB/s. It’s a much bigger improvement than I expected, especially for such a small investment.
At work where cable runs are usually made by maintenance people the most common problem is poor termination. They often just crimp a connector instead of using patch panels/sockets and unwind too much of the cable before connector which causes all kinds of problems. With proper termination problems usually go away.
But it can be a ton of other stuff too. Good cable tester is pretty much essential to figure out what’s going on. I’m using 1st gen version of Pocketethernet and it’s been pretty handy, but there’s a ton of those available, just get something a bit better than a simple indicator with blinking leds which can only indicate if the cable isn’t completely broken.