After Windows virtual machine start I've got a notification that Windows was optimized for external displays, what does it mean?
Parallels Desktop 15 brings a brand new feature which automatically detects the external display(s) connected to a Mac with Retina display and switches your graphics configuration from Best for Retina to Best for external displays mode.
The optimization takes place because of a difference between the computer's built-in Retina display and the external display's resolution to provide the most optimal settings for each user's setup.
As a result, with Best for external displays option you get a sharp picture, crisp fonts and better performance.
Note: Automatic optimization for external displays is not available in Coherence view mode.
The feature manifests according to the chosen view mode, please see the tab below:
|Aspect||Best for Retina||Best for external displays|
|Custom scaling size in Windows||Fixed 200%||Scaling is managed by Windows|
|Scaling in small window with Windowed mode||Fixed 200%, text size is convenient||100%, text size is too small|
|Picture quality in Full screen on the external display||Blurry||Sharp|
|Memory usage and performance in Full Screen||High memory usage||Average memory usage and better performance|
|Windows resolution on non-Retina display||x2 higher resolution (downscaling)||True monitor resolution|
Important: it is required to sign out and sign in to your Windows profile to apply changes and make the feature work correctly.
For more information about other video modes comparison in Parallels Desktop please see KB 124744.