Pault17- I never really checked to be exact. When I had the NC whisper daddy it seemed to do quite well. The last 3 burner I had (in the photo) was a real gas hog, even just running 2 burners. At Quad State I bought a new single burner, mid-sized, forge from the nice folks at Chile Forge. I havent got to use it but once yet so I cant say, it can run on a much lower pressure so I expect it to be quite a bit better on fuel.
I realize that was a long post & still didnt really answer the question, just my experience.