I purchased a new Dell 3847 desktop running Windows 10 at the end of July. I discovered that my after being on the internet for a period of time, my speed would slow down. When initially booted speedtest.net would show ~23 Mbps, but In a few minutes it would slow down to 1 Mbps. The slow down would occur regardless of whether I was using the Ethernet or wireless adapter. I have AT&T U-verse with 18Mbps download speed. The AT&T techs told me that my computer was soaking up all of the bandwidth of the network. This was borne out by the fact that another (laptop) computer on the network would slow down whenever my desktop would slow down and would speed up when the desktop was taken off line. Also, I would have to shutdown my desktop in order to stream Netflix or Amazon Prime. As requested by Dell, I updated all of the drivers on the desktop, and that did not fix the problem. So Dell replaced the motherboard and the wireless card in my computer. That also did not fix the problem, although today it is a little better (~6 Mbps). Before I requested a hardware repair I had AT&T replace my Gateway with the latest model and even my Fiber Optic box outside the house. I was a little dubious when the new motherboard that Dell installed was "refurbished". Has anyone else had this problem?