Hi Desperate-Dan. I don't know the answer to your speed question. The BIOS settings depend on the motherboard make and model. If you go back into the BIOS setup you should be able to tell if the changes you made were stored.
Similarly the audio connections will depend on the motherboard make and model, but as far as I have been able to determine the "HD Audio module" refers to a "High Definition" audio module that might be integrated into the motherboard, or might be a plug-in module. Let us know the motherboard make and model and we might be able to give more help.