Adaptive Quality and Display Scaling
Adaptive Quality dramatically increases performance without compromising image quality. Adaptive Quality is similar to the Progressive JPEG image file format, in which data is compressed in multiple passes of progressively higher detail. In Screens, the result is a much more responsive interface. This feature is only available with Macs and can be enabled in the app settings under More Settings.
OS X 10.6.8 Snow Leopard users should note that Adaptive Quality doesn't perform well on this platform. Enable the Scaling feature instead when connecting to Snow Leopard machines.
When this setting is enabled, Screens requests that the Screen Sharing server on your Mac send a scaled-down version of your Desktop. This is particularly useful when your Mac has several displays attached or when a 5K iMac is part of your scenario.