Wikipedia schrieb:

GDI+ continues to rely on software rendering in Windows 7.

http://blogs.technet.com/b/thomasolsen/archive/2008/10/29/introducing-the-microsoft-direct2d-api.aspx schrieb:

Direct2D (or D2D) is a native immediate-mode 2D graphics rendering API that is built on top of Direct3D, and offers some compelling performance and visual quality improvements over GDI and GDI+:
· Hardware-acceleration
...

m9898 schrieb:

Ich hatte aber auch mal ein Buch über GDI+, in dem auch stand, dass GDI+ Hardwarebeschleunigt sein soll.

GDI has been accelerated. Does anyone know when this happened? schrieb:

GDI works by calling various functions in the graphics device driver. There are a core set of functions that every driver must implement. Other functions may be implemented by the driver. If they are not, GDI will perform those functions itself.

If a particular function is not implemented in hardware then there is no point in the driver doing a software implementation of that function since GDI can probably do a better job. GDI is extremely well optimized for performance.

As more functions are implemented in hardware, not only do those functions perform much better, but there is also less work for GDI to do, resulting in less CPU time spent on graphics.

It may also be the case that the graphics card vendor, in an effort to get a card out to market quickly, may not have implemented all possible hardware functions that the card could perform. Later versions of that driver may then implement that functionality, resulting in improved performance.