Elektron Musical Instruments

I have noticed lately when creating patterns I'm getting pops and 
clicks in the headphone and main outputs.  I'm using OS 1.11, not 
using the delay function (which I heard can cause similar problems).  
I haven't noticed this on my previous recordings with the MD, just on 
the last two songs I have been working on.  This is very annoying, to 
get a great sounding MD groove going and "click" "pop"!!  Anyone know 
if this an OS problem or are certain machines more "poppy"?  I am 
stacking alot of instruments and patterns are fairly busy.  

-Scott