Windows 10 w/ Comcast Giganet Service getting only 250 Mbps

The term "Up To 1000 Mbps" doesn't mean "Guaranteed 1000 Mbps all the time on every website". Change Providers if you're not satisfied.

I seem to have similar problem. I have an optical connection and I am paying for a service called 300/300 which means 300 Mbps download and 300 Mbps upload. When I ran speedtest on my Windows 10 Pro desktop I used to get those speeds and sometimes even higher. At some point it changed to very poor upload speeds, the latest speedtest reported 216/5. My Netgear router has a built in Ookla speedtest and when I use that it shows 334/269. Also my laptop which runs Window 10 Pro Fast version and is wired to the same router shows much better results. Even a Samsung tablet connected by Wi-Fi to this router, speedtest comes back with way better results. I am pretty sure the problem is Windows 10 Pro.

I am not using any special anti-virus program, just Windows Defender. When Speedtest starts the upload test it jumps up to around 1Gbps then quickly drops down to almost 1Mbps before coming back to around 5-10 Mbps. Any suggestions?

Ak

I found out that my Internet speed problem was caused by a utility called cFosSpeed. I have used that utility for years without problem but they just came out with an update. After uninstalling that utility, Speedtest now comes up with 246/226 for download/upload Mbps so I am happy.