I don't think bigger buffers really need more CPU time. Just a little more memory.
Â
Bigger buffers are better for sound quality as they make the sound stream more resistant against the problem that new audio data might come in too late (when all the buffered audio data has already been played back).
Â
Unfortunately, the drawback of bigger buffers is audio lag. (The difference in time between you pressing a key + the emulator producing a noise and the actual time that noise reaches your speakers).
Â
Â
I have seen sound cards which produce pops & clicks when a buffer runs dry, and others where there is just silence (which sounds much less disturbing).