Just a general thought, perhaps the computers were running more high-impact processes, compared to the other. Of which would slow down your speed of download. Try looking at this discussion for a more helpful insight; https://support.mozilla.org/en-US/questions/945247

Hi, No neither PC was running anything else at the times it was tried. Downloads via filezilla run at the same speed on both machines and also downloads in other software. It is only firefox where this is a large discrepancy between the two machines on file downloads. The slowest machine is the newest one that has less overheads than the older one.

regards Steve

Windows 10 Microsoft substitutes it's own drivers on some hardware. It is possible that this happened. Check your Device Manager and see if the Drivers have been swapped out for MS ones. If they have or if have not it would be a good thing to check to see if there is updated drivers for your Network Cards/Lan

Also some companies will restrict the use of how many computers can be hooked up to them at the same time. Check with tour provider to see if there is restrictions. I have a limit of 3 Do not know if that counts with mobiles also.

Also this may be of use : https://www.howtogeek.com/302595/how-to-stop-windows-10-from-automatically-updating-hardware-drivers/

And can try this : https://support.mozilla.org/en-US/kb/firefox-slow-how-make-it-faster

Could be a OS issue : Repair System Registry and Files

Run the Windows Deployment Image Servicing and Management (DISM) and System File Checker (SFC) tools as Administrator. The DISM and SFC tools scan the integrity of the Windows image and all protected system files replaces corrupted, damaged and incorrect versions.

To run the DISM command use the Windows key + X keyboard shortcut to open the Power User menu, then select Command Prompt (Admin). Type "DISM /Online /Cleanup-Image /RestoreHealth" (without quotes or copy/paste) and press Enter. While running DISM you may notice the process will appear to pause at 20%. After a few minutes the operation will continue.

To run the SFC command use the Windows key + X keyboard shortcut to open the Power User menu and select Command Prompt (Admin). Type "SFC /SCANNOW" (without quotes or copy/paste) and press Enter. For more information on using SFC, please refer to the Microsoft KB: Use the System File Checker tool to repair missing or corrupted system files

Please let us know if this solved your issue or if need further assistance.

Well I am not sure what I did to solve the issue, as I tried so many things to no avail. However, today when I booted up, firefox is now downloading on the affected machine at over 4MB/s now faster the the other PC!

Some of the steps I took were:

• Enabled netBios over TCP on the IP4 configuration.
• RE-Downloaded and installed the network card drivers.
• Changed some Network settings in Firefox about:config
• Flushed the DNS cache

and re-booted.

However, these steps didn't improve the download speed yesterday. Today on a new boot up, the download speed has miraculously improved.

Just hope it continues to perform this well.

regards Steve

Thanks to those that replied and offered help.