I've just done a fresh build of the latest HMH (as of day 431). It's running around 1 frame per second, with 97% of the time going into OpenGLRenderCommands() (and task manager shows the GPU maxed out at 100%, with cpu around 40%)
This is running on a relatively old (4-5 years?) GTX 760 - should I just accept that the shaders in HMH are doing too much for my gpu, or does this sound like something else is off? Is there a way to further isolate the cause, or is it all black box once you're in OpenGL land?