Hi, where are you uploading them to ? If a website why not use Filezilla FTP instead ?

Delete your cache and cookies.

Check if Win 10 is limiting your speed : https://www.ghacks.net/2016/08/05/windows-10-limiting-internet-speed/

What kind internet are you suppose to have ? Are you on Broadband or a DSL or wifi ? www.speedtest.net/

I can not find anything.

I do use filezilla for other things but i have to upload to a website using a web browser.

it was a completely clean install of windows. There were no cookies or cache and the very first thing i tried was uploading.

Edge and Chrome are not affected why would windows only effect firefox. I read about the windows thing you posted and i dont want to mess with the settings.

I'm using xfinity and directly connected to my modem.

I tried like 5 different speed tests and they all upload at the proper speed. Could it be an issue with the site itself? why would it only effect firefox and not Edge or Chrome. I know that last part is beyond the scope of this support forum.

Thank you for your time though. It is appreciated.

First time ive heard of this. Try some speed boasters software for speed settings. FF is pretty basic and dont think it has a limit on speeds. could be some configuration like a vpn or antivirus filtering its speed. Could also be some sort of addon.