Wow! Actually only the water detail was the problem, everything else is on the highest and the water is on minimal. If I put the water higher the solid 30 fps drops to 11 and lower. I don't know why is this happening and why wasn't it a problem before but I'm glad that it has been resolved.
EDIT: This is working in debugging mode, in the exe file I have to change the resolution to 800x600 too to make it work. 1× editiert, zuletzt 30.06.17 14:45:57