Whenever I open the "Saturn with rings" simulation, I can see only a ring composed of several quite huge rocks, without any planet, although I see a Saturn label in the middle. After adding Saturn manually, it won't help the rings to stay at place because I can't fit it exactly into the center. And the planet disappears after a while, although it acts as if it still was there and I can normally select it (second screenshot)
I also get a framerate of 1fps during this simulation, while solar system simulation gets me 12fps. It seems to not change at all even by turning off / on anti aliasing, effects or texture quality.
Intel i5 4670K @ 4.0GHz
GTX760 2gb VRAM
8GB RAM