If you saw a performance increase, try nipping over to Harkonnen thread and explain that you got a performance boost but still get CTDs, also tell them the settings you used in the Harkonnen patch. They may have a suggestion or two for you.
Just to check the obvious when you apply that patch you unzip files to the Civ IV directory, one file needs overwriting (that must happen or the patch will not run), did you get such a request when unpacking (eg something like ......ok to over write ..... etc, if you didnt, the patch was not loaded properly
EDIT: You said newer driver, have you tried rolling back to an older one ? The issue there is that drivers and the software base for the Beta tests on which the Release was based will have been frozen some time ago (cant Beta test if you keep changing the software base), and newer less stable drivers can cause issues, no guarantees, but many have found older drivers circa 6-9 months older work a lot better, may not work for you, but worth a go
Regards
Zy