There are an awful lot of things that could make this happen, and a large amount of threads here on it.
This is a link to the main thread on the issue.
It is the #1 issue on the Bugs Feedback Snapshot
You could also ust the search function at the top right of the page for
Stutters CTD
There are a lot of returns on that topic, you will need to scan through and see if any offer some advice for your specific issue.
Good luck, let us know how you make out