I've kept all my PCs in the same area for years, and the internet connection has never been great on my computer. What's going on? My other PC is way farther from the router than this one, yet it reaches the speeds my company offers. I've used various antennas, different Wi-Fi cards, even the one in the other PC, but the connection remains poor. Check this out: my PC's Wi-Fi speed versus my phone's internet speed (tested in the same room) and my other PC's connection.
Looks like a poor-quality Ethernet connection to me as well.
There are plenty of long cables available. As long as you choose a high-quality one, you can achieve much faster performance. It’s best to select a cable that fits your baseboards and run it along them. I’ve done this in various areas of my home, and the result is a subtle highlight on the baseboards (white on white).
Yes, adjusting the position helps occasionally, but it rarely exceeds 20mb/s.
Also, the antenna I currently use is: http://www.helptechco.com/content/TL-WN781ND