What else is running in the background when this occurs?
What type of content are you viewing when this occurs? (quicktime video, video in iTunes, youTube, Safari, Chrome, etc)
If it is video in iTunes or with Quicktimex, it is most likely related to a known Mavericks issue that we are working on. Waiting on word from Apple. See this thread https://www.bongiovidps.com/forums/topic/mavericks-osx-issue-list/
Try closing out other programs and see if this issue persists. I will await your reply.