Well thought demonstrably takes effort, a ridiculous amount of your bodies resources is spent on thinking, however it's hard to pin this down in a certain 'rate

Well thought demonstrably takes effort, a ridiculous amount of your bodies resources is spent on thinking, however it's hard to pin this down in a certain 'rate'. You could probably show that calories and certain other resources get exhausted by concentrated thought, however in my experience this has little to do with speed of thought and everything to do with depth (the only times I truly felt mentally exhausted was when I was trying to dig up deeply buried fragments of memory to solve a maths problem).