@Bolbi: as I said, I got the same results on Firefox 3.6.8 on Linux than on a Direct2D-enabled Firefox 4 build on Windows.
Why?
Because ever since Firefox 3.0, all rendering is done through the Cairo library, which has several backends available, among which:
- win32 (legacy Win9x/WinNT5.x),
- xlib (X11 library),
- RENDER (an extension to xlib),
- Quartz (the Mac graphics layer).
Well, it so happens that on Nvidia hardware, the RENDER extension is as fast as Direct2D on very fast blittings like those found on the "Psychedelic browsing" test.
Which is fun. Is all.