Firefox slow after windows 10 upgrade but Chrome and Microsoft Edge OK

After completing the Win 10 upgrade process everything looked really good....until I started browsing the internet.
All my browser's are slow as molasses and getting tons of connection time outs.

Anyone else having the same problem?

Are you using Edge?
If so the default proxy setting is incorrect, change it

After completing the Win 10 upgrade process everything looked really good....until I started browsing the internet.
All my browser's are slow as molasses and getting tons of connection time outs.

Anyone else having the same problem?

I'm having similar problems. Firefox is crawling along but Chrome and Edge seem to be slow but OK.

Are you using Edge?
If so the default proxy setting is incorrect, change it

What is incorrect as it's on Automatically detect settings and what should one change it to?

Hi Almighty1, Auto detect is correct
Do you have other browsers installed and if so then are they unaffected?
Try running sfc/scannow (run at least 3 times)
Assuming other browsers are OK it's unlikely a connectivity issue per se
However, try MiniToolBox, see here

I'm not having any problems yet but was just curious what you meant earlier by the proxy setting being incorrect.

Sometimes drivers are the issue, graphics drivers, etc.

Does your motherboard/computer manufacturer provide you with the specific Win10 drivers for your system?

In addition, here is a tutorial on potentially speeding things up: Optimize Performance of Windows 8 - works in Win10 too!

See this post regarding Edge proxy issues, see here
Check the DNS settings for your adapter (if it's DHCP then check the router settings)

After completing the Win 10 upgrade process everything looked really good....until I started browsing the internet.
All my browser's are slow as molasses and getting tons of connection time outs.

Anyone else having the same problem?

Yes, I am have the exact same problem. I am running Windows 10 Home and had to do a restore point in time to fix temporarily until I figure it out.. Windows update will automatically run again with the same KB3199209 update.