I read about some problems with multithreded rendering in the past, but have heard nothing about it recently. I’d like to try it out, so…
How is Multithreded rendering option in the build with Unity 5.0.2? Is it stable now?
P.S. Please if you’re not sure but have experience with it, write a comment 
Unity currently doesn’t support multi threaded rendering. Not only Unity, most of the game engines do not support this feature. Because all of them are using OpenGL library.
A good news is that, OpenGL community, the Khronos group and some other open source graphic developers have developed the Vulkan API, which is far better than current graphics API standards. The current graphics standard is more than 25 years old.
The advantage of Vulkan API is support for multithreaded APIs and pushing all graphics processing tasks to GPUs, taking advantage of multiple GPU cores or multiple GPUs. I 've heard that Vulan API is much better than Apple’s Metal API. It gives full native access to the developers. Most of the graphics driver related tasks can now be handled by game engines.
Hope for Unity to support Vulkan. Unity team have been taking advantage of all new technologies and trends in computer graphics and games.