theme settings | Tech Off

UB hans gunsche

i really don't care much about the way windows vista looks. i was told awhile back that by setting the theme to classic settings acutally dumps more work onto the cpu and gpu and i am just curious if to this is true.

littleguru
<3 Seattle

If you disable Aero most of the rendering work (as in rendering the contents of the windows) is done on the CPU. With Aero (the glass stuff) most of the stuff is rendered directly by the GPU and therefore less load is on the CPU.

The classic theme (and all others that don't feature the glass) disable Aero.

Dexter

In reply to littleguru

#May 4th @ 6:55 AM

Not quite. Remember that Aero (aka DWM) is only a window manager. It paints the window title/border and blits the client area onto the screen. How the client are is drawn depends on what graphics API the application uses, not on if Aero runs or not.

Some application like Office is not hardware accelerated because it uses GDI/GDI+ and these APIs are not hardware accelerated on Vista. A game that uses Direct3D will be hardware accelerated even if Aero is not running.

W3bbo
The Master of Baiters

In reply to Dexter

#May 4th @ 9:26 AM

I'm getting mixed messages about acceleration of GDI on Windows.

Apparently regular C-style GDI has been hardware accelerated by 2D cards ever since 1995. The object-oriented GDI+ however is always done in software except for operations like blitting which is usually done in hardware.

...and in Vista C-style GDI is no-longer accelerated?

Dexter

Yep, "mixed" is the right word. Until Vista (or maybe more correctly until WDDM 1.0) graphics drivers could imlement some (maybe all) of the GDI functionality in hardware. Then Vista came out they said that GDI is software only. In Win7 the GDI acceleration seems to be back.

See here for some details: http://blogs.msdn.com/e7/archive/2009/04/25/engineering-windows-7-for-graphics-performance.aspx (the section about "reducing memory footprint").

PS: GDI+ is actually a C-style API too. The C++ version is a thin wrapper "implemented" only in header files, the GDI+ dll only exports C functions.

AndyC

Up to XP, 2D drawing via GPI was usually hardware accelerated. In Vista this was removed and the only hardware acceleration is that done by Aero. So, on Vista, it is true to say that switching off Aero puts a much larger burden on the CPU.

Windows 7 restores some acceleration for GDI when used with WDDM 1.1 drivers. It's still done via the 3D card though, so you presumably still need Aero enabled to benefit.