We're currently gathering further information for development and we'd appreciate your co-operation. Could you please send us the following:
* process monitor output from while it's happening
you can find the tool here: https://docs.microsoft.com/en-us/sysinternals/downloads/procmon
* a process dump
you can generate it by opening the task manager > right-click on the process that is using the bandwidth > "create process dump"
* a wireshark capture if possible
you can find the tool here: http://www.wireshark.org/download.html
After downloading, go to menu "Capture" -> "Interfaces" -> "Start"
Induce the issue resp. simply start the recording during a period where you are experiencing bandwidth issues
Stop recording and save the results
Please upload the resulting files to our FTP server and let us know the package name via your case you submitted.
Avast FTP server instructions: https://support.avast.com/en-us/article/FTP-file-upload
Process Monitor - Windows Sysinternals
When you contact Avast Support with a technical or malware-related issue, you may be asked to upload specific files from your PC to the Avast FTP server for further analysis.
Feel free to contact us if you have any further questions.