Hey, I updated the builds again - if someone who uses OSX could try this one, that'd be helpful.
If you press the 1 key, you can see the profiler and see the GPU wait time (if it's greater than 0, then that means that the rendering process is slowing the game down, which is in line with what you mentioned, rainybyte). Also, I adjusted the lighting a bit - try turning off advanced lighting to improve the framerate, if the game runs slowly.