problems with audio output

It seems that anytime I set the MPC's audio output as the renaissance, I always get occasional pops and clicks. It doesn't matter if the buffer is at the standard 512 (though I normally work at 128 since my macbook runs on 4gb) or if the MPC program is the only thing running w/ wifi turned off. Be that as it may, it's pretty much impossible to use this thing as a live instrument without either latency, lag when I press the stop key, or the pops and clicks.

Any ideas on how I can fix this?