I've recently come into possession of this ASUS PCI-AV264CT-N MediaBus card, which is a combination of an ATI Mach64 and a SoundBlaster Vibra16C.
What I'd like to do however, is figure out some way of disabling the Mach64 chip, as I already have another graphics chip that I would like to use in this system, but still be able to use the SB16 on it.
I noticed the card had some jumpers, two of them above the feature connector under some capacitors (JP2 and JP3), and one of them under the bios chip (JP8). I was hoping these were related to disabling However, I have been unable to find any information on what the function of these are. There is no information documented in the manual for this series of cards, nor anything else on the web that I could find. (The only manual I could find was a relatively generic manual for the entire AV264 series) .

Now following the traces on the board, it appears that JP2 and JP3 have something to with the sound chip, as JP2 seems to be connected to the TEA2025B chip's VCC pin, which is a stereo amplifier. That would make sense as the other end is connected to a capacitor, so likely this allows you to disable it.

JP3 seems to be connected to the SPK OUT through some sort of resistor. I'm not sure as to what end, but it's also connected to a capacitor. I'm theorizing it may have something to do with stereo/mono mode, but that's just a guess.

While I'm still curious to find out if they have some sort of purpose to the user, JP8 might be more interesting.

Following traces here, this appears to connect to the VCC pin on the BIOS chip. I'm not sure what the other side of the jumper connects to, it doesn't seem to have a distinct trace, but it may be interesting.
I haven't removed this cap yet, as I want to avoid damaging this card as it seems to be quite rare. It does seem like it might disable the VGA BIOS. Maybe someone here knows if removing this cap is dangerous.

Any assistance would be appreciated greatly