Audio popping/clicking can occur when putting two clips next to each other without any audio transition because the last sample of the first clip might be very different from the first sample of the second clip - which causes a pop. If this applies to you, try adding audio fade in/out filters to the clips. Or apply a transition.
Have you tried to adjust volume level on each clip as you are doubling up on clips, what about normalize?
The reason may be that you have too many "jobs" running on the machine at one time. Try and close all other jobs and make sure that your program (if magix music maker) only uses WASAPI driver for your sound card. At first glance, I think it's because you overload your PC so it can not keep up with the processor. My prof. Is the prof soft / hardware. I have occasionally experienced the same thing, so jobs have to be shut down so that there is power to what I require of my i7 machine. regarding Finn