Simple Questions Simple Answers - Page 497

On September 05 2014 00:21 Cyro wrote:
Windows 7 allows you to disable vsync on desktop and when playing games in anything but exclusive fullscreen mode - by switching the theme type away from aero themes, which is a feature that i can't live without. AFAIK, it doesn't exist in win8/8.1, so you're forced to have laggier input.

Double check that though, i'm not certain

To clear this up, Aero is technically the transparent glass theme used in Windows Vista and 7. A modified version was used in Windows 8 up until the Release Preview.

Aero only can be displayed while the Desktop Window Manager (DWM) is running, as it is the compositor that allows these effects to function properly (layers windows in 3D space rather than painting them pixel by pixel). In Windows Vista and 7, DWM required GPU acceleration (supporting DirectX 9.0c and WDDM driver) to function. To paint the UI without that, the older GDI methods of painting windows by the rectangles and the pixels was needed. Disabling DWM service also disabled the Aero theme (putting it into basic). Using the basic theme or classic theme disabled DWM, as it wasn't being used to display those themes. High contrast themes used classic theme, and setting everything to 'best performance' disabled both DWM and themes (causing the classic theme to be used). GDI was the fallback, which used the CPU to paint the windows the old fashioned way. Because they aren't layered and composited, a window covering another one caused the window beneath it to require a redraw of everything when the offending window was moved away. This is why you see so many weird artifacts when you drag windows around real fast in XP or Vista/7 basic/classic theme.

In Windows 8, DWM was upgraded so that it could render the desktop in a composited 3D space even without WDDM graphics drivers or GPU acceleration present. They achieve this by putting all this workload on the CPU instead, aka 'software rendering'. GDI to draw the desktop window elements has been removed, save for drawing the individual buttons and controls inside a window perhaps (for compatibility). In the RTM, DWM functions to make window borders transparent and blur transparencies was removed. As well, they modified the Aero theme to be extremely flat and basic looking, with no gradients or detail whatsoever. However, the technology that powered Aero (DWM) is still running, this time, as an always-on feature you cannot disable. DWM being always-on was necessary for the smooth animated experience of the 'start screen' and 'metro apps' being able to overlay the desktop without worrying about redrawing obscured windows, as well as taking advantage of GPU acceleration (when available) to keep the experience smooth. Disabling DWM or trying to compromise the theme would give you a giant black screen or an otherwise unusable Windows 8 desktop. Obviously, this means they removed the ability to disable DWM.