Can anyone tell me why I'm experiencing pops and clicks on playback when I don't have the same issue running an identical project in Reaper? My audio interface is a Fractal Audio Axe-FX 2 running via USB but this project contains only MIDI software instruments, no audio. Logic buffer size is set to 32 (although I have tried other settings). None of my track levels are running into the red. My machine is a 2007 iMac with 4GB of RAM.