By forcing some buffers to use the video RAM rather than the GART/GTT system memory, Marek managed the 4x OpenGL performance increase on the R600g driver for the Reaction Quake 3 game.
The patch surfaced today on the Mesa mailing list. "The problem was we set VRAM|GTT for relocations of STATIC resources. Setting just VRAM increases the framerate 4 times on my machine."
For those wondering about other possible performance optimizations for the open-source Mesa/Gallium3D drivers, Alex Deucher of AMD wrote in the forums that better heuristics for better buffer placement and buffer upload/caching can be a win as well as shader compiler improvements, cached and uncached GART memory usage, and better 1D/2D/linear tiling selection heuristics.
Among the missing OpenGL features for Radeon HD 2000 through HD 4000 graphics cards at the moment include geometry shaders, multi-sample textures, uniform buffer objects, and texture buffer objects, wrote Marek in another post.