Investigate d3d9 GDI overhead with >2005 (< ?) directx sdks

[mirh]

Follows #164 (comment) and assuming d3dx is even something that you (can) care.
It turns out that my weird observation is the result of a directx sdk change. Up until the december 2005 version, I get the high numbers.
Starting with the one from february 2006 (not sure about the latest, but still) I'm getting half if not even less the framerate.
Under wine, there is still a nominal difference, but it's leaps and bounds lower.

This is the breakdown of the sample internals:

While this is the stack for every one of those d3dx9_29.dll calls

Is there something that could (and should) be done to avoid this?