Stefan Dösinger of CodeWeavers has been working on some Direct3D performance improvements for Wine by creating a separate command stream / worker thread for WineD3D. This work moves OpenGL calls into a seperate thread in order to improve performance while also fixing some outstanding bugs. This work can yield 50~100% performance improvements and in some cases making the games under Wine faster than on Windows.
Stefan published on Monday the set of D3D command stream patches that go against Wine 1.7.1 and improve performance by offloading the drawing calls onto a separate CPU thread. These improvements though won't help out current GPU-limited games and is similar in nature to NVIDIA's threaded OpenGL optimizations from last year.
In announcing the work, Stefan noted, "A lot of games see 50%-100% performance improvements and now run as fast as on Windows or even faster. Examples are Source-Engine based games, StarCraft 2, 3DMark 2001...Call of Duty Modern Warfare 2 is improved a lot because you no longer need StrictDrawOrdering. It's still not as good as it could be, because it uses dynamic surfaces, which aren't properly implemented in the patchset yet."
For those interested in a lot more detail on this work that has yet to be merged into mainline Mesa, check out the wine-devel mailing list
for the patches and more information.