I have the strangest problem. If Firefox is closed and I do a speedtest in another browser, download a file, or do other internet activity I'm getting about 200-250Mbps … (read more)
I have the strangest problem. If Firefox is closed and I do a speedtest in another browser, download a file, or do other internet activity I'm getting about 200-250Mbps d/l and 100Mbps upload. As soon as I open Firefox, whether I load a page or not, the upload speed stays the same, however the download speed drops to about 25-50 Mbps. This only happens on one PC, the upload isn't affected, and resolves itself as soon as Firefox is closed. Here's what I have done without any change in this behaviour;
- Rebooted
- ipconfig /release /renew /flushdns
- Removed and reinstalled the network adapter
- Enabled, disabled windows auto tuning and tested (slower disabled)
- Updated Windows
- Refreshed Firefox
- Uninstalled Firefox, deleted remaining folders from Appdata (Local, Low, Roaming) as well as the program file directories and "Mozilla" registry entries. Restarted and reinstalled. Issue immediately resumed when Firefox was open.
Also when connected to a VPN Firefox download speed increases to about 60Mbps and is consistent across other software. If I split tunnel another browser outside the VPN, it is still stuck at 60Mbps. If I close Firefox the speed increases.
This makes absolutely no sense to me, so I'm hoping someone can shed some light on this - but it does seem to be something Firefox is doing.
Thanks for any help anyone can provide.