Here is a "quasi-letter" statment from Warren Spector from ION Storm on Deus EX and D3D performance:
When we shipped Deus Ex two weeks ago, we knew the game performed better with some video cards than with others. For us, the performance problems seemed minor and highly configuration driven. Internally we were able to tweak game settings to achieve acceptable performance. That seemed like enough of an answer.
You guys quickly set us straight on THAT subject!
Within days, we started seeing messages, lots of them, about D3D performance issues and immediately set to work trying to find a solution. At that point, as regular readers of usenet and the various DX message boards know, we fell silent on the subject of D3D issues. Some of you took our silence as a statement that we didn't care or weren't paying attention. 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.
We didn't want to say anything publicly until we had a solution but now, we think we've found one.
At http://www.eidosinteractive.com/techsupp/deusex/patches.html you'll find a file called "D3DDrv.dll." If you're using an nVidia, Matrox or other D3D card, you really want to get this file and, following the instructions at the download site, give it a try.
We've done a fair amount of testing on this. We're seeing dramatic framerate improvements (and, obviously, significant gameplay enhancement!). But, as I said, a lot of the D3D problems seem to be configuration dependent and we need to hear from you before we change the patch status from "beta" to "final." Let us know how it works for you.
And if we're right, if this does fix Deus Ex's "D3D Performance Problem," please tell your friends. We obviously have a vested interest, but we'd like to hear how people like our GAME rather than what people think of our framerate...
Related Links: Deus EX Patch - DOWNLOAD NOW!