clicking means the buffer gets emptied. Faster CPUs need smaller buffers. The only ways to fix this are reducing CPU usage or increasing audio buffer size (which in turn increases audio latency). No idea if this is possible within construct.
I haven't noticed any issues with sounds clicking or popping at all. Can someone post a .cap? I guess if you don't autoplay and play sounds on fixed channels (which is a bad idea), you'll interrupt playing samples which could click.