Speed Test Loggger for Windows

Logs your download speed and internet outages over time.

Download installer

Run Logger_Setup.exe. It installs .NET Framework 4.8 if needed, then installs the app. The app checks for updates each time it starts.

The main window, with a graph of download speed over time and the list of test results

Upgrading from version 1.3 or earlier? Uninstall "Speed Test Loggger" from Settings → Apps first. Your log is kept.

Source on GitHub