Performance Issues 1.13 vs 1.12

When I create a standard new world and fly around (e.g Spectator Mode) the average Framerate is the same in 1.13 compared to 1.12 = ~200 FPS.

The mininum Framerate is in 1.13 about 20 FPS, whereas in 1.12 it stays always above 150.

Tell me if you need any other information