Eidos released a small patch today for the performance issues experienced by some users when running Deus Ex in Direct3D. The update should correct frame rate problems due to texture thrashing on Nvidia and Matrox cards.
In a statement about Direct3D issues and the new patch, Warren Spector said, "Trust me, we were paying attention and we did care. Each flaming thread about D3D performance was like a dagger to the heart. Well, we think it's time to pull the dagger out and cauterize the wound."
Follow the link below to find the small patch and installation instructions.