? Are you trying to tell me that GDI wasn't directly accelerated in pre vista, non win9x OSs?
Because I believe you to be strongly mistaken. From the windows 2000 XDDM reference, GDI functions Implemented by printer and display drivers:
You will notice that everything from font rendering to curve drawing, path filling (yes with xor), you name it _CAN_ be implemented although only a small subset is required. _BUT_, I would say that most were implemented by the better hardware manufactures for the common video resolutions.
You will also notice that the documentation has been updated and says "The functions documented in this section are implemented by printer drivers and by drivers in the Windows 2000 display driver model, but they are not implemented by drivers in the Windows Vista display driver model." This is also directly noticeable in GDI benchmarks between the two OS's (especially when run on slower CPU machines, or while monitoring CPU usage). There are also a fair number of youtube ( for example https://www.youtube.com/watch?...) videos of people showing things like the scrolling speeds in explorer on XP vs vista. 7 improved the situation slightly, but as of a few years ago the benchmarks I remember seeing were still strongly tilted in XP's favor if one monitors CPU usage during the benchmark.