I have an HP nw8440 that uses the TI SD Card Reader. The reader worked perfectly for XP and Vista Enterprise 32-bit, but would not read cards greater than 2GB in size after my switch to x64.
I was able to follow the procedure at
Integrated Card Reader 4GB SD Success - Notebooks - PC Hardware to get my card reader working in Vista Enterprise x64.
I used version 2.0.0.8 of the drivers downloaded from
HP Compaq nw8440 Mobile Workstation*-* Texas Instruments Media Card Reader Driver - HP Business Support Center.