Mat, I’ve had the exact same problem and it seems that a lot of users have had this issue with 2.7.3. I’ve found that if you zoom into the waveform at the points where the sound issues are, it can be seen that there are audio gaps and omissions repeatedly in the track. Therefore it is not a sound card issue, but in fact an issue with the software. When I’ve reverted back to using 2.6.8 there is no longer such issues with the audio. Therefore it seems to be an issue with 2.7.3. I’m waiting on a reply from the Native Instruments support team with regards to this problem but if it’s simply a glitch in the software hopefully it will be fixed soon with an update. This guy shows the problem, where it seems to be a bit more extreme in his case: https://www.youtube.com/watch?v=up7cXUOYNok
