Task Manager on Windows 10 is blurry on secondary monitors if they have a different DPI from the primary monitor. This is because Task Manager is only PROCESS_SYSTEM_DPI_AWARE, despite being a relatively new application (a new Task Manager was introduced in Windows 8). This can be confirmed by using a tool such as Resource Hacker and checking the manifest file for this:
<asmv3:windowsSettings xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">
<dpiAware>true</dpiAware>
<autoElevate>true</autoElevate>
</asmv3:windowsSettings>