I want to know the reason when I play the music , It has a music shortly disconnection problem such as a buffering.

refer to blow specification

1. Computer System
  - Haswell imac27 3.5 i7 / NVIDIA Geforce GTX 780M
  - OS : osx 10.9 Mevericks
 
2. Audio Device
  - RME Fireface UCX
  - Port : USB

3. Symptom
  - When I play a four minutes music , the disconnection problme appeared 2 or 3 times
  - Even I meet the problem on Logic X, Movie Play and Youtube

One more important thing is "there is no problem on the Macbook pro 2010"

I don't know weather is computer problem or driver problem

please let me know if you have any solutions before.

As soon as possible to reply me , thank you .