The PCI spec is at 32 bits. ISA slots were 16 bits, and like your mb, there are 64 bit slots out there.
That is a completely different thing than audio.
Audio cards are generally 16 bits at the consumer level. Newer cards for high-end comsumers have already reached 24 bit/96khz already though.
So you can have a 24 bit card run on an ISA slot (16 bits) if there was one available.
Regardless of the PCI bus or PCI express, PCI X, or any other bus. Most likely future cards will be at 24 bits for a while.
In the case of graphics cards, their processors run at 256 bits for current cards, they can display a maximum of 24 bit color with 8 bits used for alpha blending I believe.
Most graphic files are actually 8 bits, with video cards like
the Matrox Parhelia (Maybe current ATI cards) being able to display 10 bit pictures. 10 bit precission just adds to the amount of colors being able to be used.
So pretty much everything has its own bit settings. And one does not depend on the other unless being bottlenecked by another component.
So we will have 24 bit recording/playback for a while.
These explanations can be dragged on and on, I just scratched the surface.
If I made a mistake on anything, please feel free to correct me anyone. It's appreciated.
