Before I start, I should mention that I am a Linux newbie, and while I can do anything you tell me to do, I would prefer to know why it works as well.

I recently formatted my hard drive and re-installed Mandrake 9.1 because my modules.conf became heavily corrupted. My previous install worked perfectly in terms of sound. Now, however, everything related to sound is either choppy, or very laggy. (e.g. in XMMS pushing pause takes 2 seconds to fully stop the music, and changing the song overlaps the two songs for a couple of seconds.)

I have a reasonably fast computer (1.7 GHZ) with an onboard ALi sound card, as well a SoundBlaster Live! Value card. Mandrake configured both of them on install, but I'm not sure which it is using.

Any help with this issue would be very much appreciated.

Can you go into the bios and disable the onboard card? If so, do it. Then, Mandrake should use the SbLive. That should help.

I tried doing that way back when I was only using Windows. It seems that my BIOS won't let me disable the sound card. It gives me the option but won't register the fact that I try and disable it. Plus, Linux doesn't output any sound on the ALi card. So, now I'm at a complete loss for what to do......thanks anyway, though.

Sounds liek you may have to manually diable the onboard sound. Usually taken care of by Jumpers on the motherboard. If it's an older P3 board then thats most likely the case. If it's a newer board then it should be in the BIOS.
Most everything on new boards is taken care of in the BIOS.
But check the motherboard jumpers anyhow.
>>peace<<