Garageband '11 Buffer Size

I created a track in GarageBand '11 and it has weird clicking noises in the background. Someone suggested I increase the buffer size, but from what I can tell, it doesn't have that setting... Is there any setting equivalent to increased buffer size that could produce the same result?
Thanks!

What exactly do you mean by "weird clicking"?

Did you record audio on a "Real Instrument" track using the built in mic?