I have had the same, image freezes for several seconds and then the game resumes. And I got that in Red Orchestra 2 too, which also uses unreal engine.
I turns out my problem came from 334.89 Nvidia drivers, I don't have this problem anymore now I came back to 332.21. It solved my problem in both games.
Now only problem I have with renegade X is a freeze forcing me to kill the process, which is very rare about 1 freeze in a 4 hours session (and the well documented map changing bug).