so I created a small isle using a Unity-Terrain object and Unity Water4Example (Advanced). Nothing to fancy, but I noticed some annoying stuttering issues most noticeable in the Terrain texture and the horizon. My frame rate was at stable 75fps. After hours of testing and reading in the Forums I finally figured that the Terrain was causing all that trouble.
I just rebuild the base of my isle in my favorite 3D-App and disabled the Terrain. Everything works perfectly fine now.
Is that a known issue? Maybe its system specific, but I thought it might be interesting for some of you experiencing that stuttering (lagging behind).