[kde-doc-english] System Settings: Desktop Effects

[Jay Starkman]

Suggestions for adding an Advanced section in the Table of Contents:

------ Existing ------
Advanced tab
On this tab you can select a Compositing type (OpenGL or XRender) and
set some options for the selected type.

------ Proposed New ------
Advanced tab
On this tab you can select a Compositing type (OpenGL or XRender) and
set some options for the selected type.

XRender is slower than OpenGL.  It only uses 2d acceleration but is much
more compatible and works with older graphics cards as well.  Desktop
Cube Animation (General Settings) cannot be activated when using
XRender.

OpenGL is the fastest solution as it uses your graphics card's 3d
acceleration for rendering.

OpenGL Options.
 
Texture From Pixmap stores the texture directly in the graphics
card's memory, and is usually the fastest option.

Shared Memory stores the textures in X's shared memory, which resides
in the system RAM and is usually much slower than the graphics card's
memory, especially when there is a secondary video card.  However,
Shared Memory is always faster when you are working with an integrated
video card because, lacking its own memory, the integrated video chipset
uses shared memory.  The graphic driver gives the system the illusion
that it isn't using shared memory, but real video memory, and this
illusion involves conversions that incur in additional performance
penalties.  Exception: if you have an integrated video chipset WITH
MEMORY, "Shared Memory" will be slower.

Fallback tries Texture from Pixmap first and Shared Memory if that does
not work.

Enable Direct Rendering passes the commands directly to the graphics
card and bypasses the X server. This is much faster as it the commands
have to be copied less, but can be more instable and less compatible.

VSync (vertical synchronization) ensures that the pictures are drawn in
sync to the vertical display updates. This can be more soothing to the
eyes, but is a little slower than just drawing the frames any time the
graphics card is ready to do so.


adapted from:
http://webcache.googleusercontent.com/search?q=cache:OOfV4PQ3DOIJ:linux-tipps.blogspot.com/2008/06/kde4-kwin-desktop-effects-howto.html+opengl+pixmap+vs+"shared+memory"&cd=10&hl=en&ct=clnk&gl=us&source=www.google.com


----------------------------------------------------------------------
Author of "The Sex of a Hippopotamus: A Unique History of Taxes
and Accounting" at www.starkman.com/hippo

Jay Starkman, CPA              Voice: 404-636-1400   Fax:404-636-1130
1431 Stephens Drive            e-mail:   jay at starkman.com
Atlanta, Georgia  30329        Internet: http://www.starkman.com
----------------------------------------------------------------------