So about 3 weeks ago I had AT&T Uverse Gigapower installed. I was supposed to get 1 Gig down and 1 Gig up. They came and installed it, and speedtest revealed I was only getting about 580 megs down and roughly the same up. Which is below their standards of 600 megs down. I told the guy it was close enough and I would deal with it. Over the past two weeks, random tests indicate its dropped down to about 480 down. So I called and had a repair tech come out yesterday. He couldn't find anything wrong with the line. He wanted to blame the computer. The computer is "3 months old". Really its a late 2015 iMac that I purchased new 3 months ago. It has 32 gigs of Ram, 3.2ghz processor. He told me maybe my ethernet card was bad. I showed him netstat which showed I was connected to a gigabit connection, that it was indeed recognizing. He left agreeing sending it to his engineer team to see what they can do. After he left, I went and bought Windows 10, and installed it on bootcamp. Everyone kept asking me do I have another computer to test with, and that was the cheapest option to put that argument to rest as technically it would be another computer. To my amazement, after getting everything installed, I ran the test and Windows 10 was pulling 820 megs down and roughly the same up. So my questions are what settings in OS X are preventing me from seeing the same speeds that Im getting in Windows 10? Because that is literally the only thing that is changing. I had El Capitan, and it was the same issue. I upgraded to Sierra, hoping my speeds would improve. Are there any tweaks I can use to get more speed out of OS X? Ive used Namebench to get the best DNS servers and inputted those. Anything else?