On a Mac Mini quad core i7 running High Sierra with 0.19.0-Beta1:

$ time /opt/local/x86_64-apple-darwin/bin/dcraw_emu -h -w ~/Downloads/fujifilm_x_t2_01.raf

real 0m0.988s
user 0m2.885s
sys 0m0.183s

$ time /opt/local/x86_64-apple-darwin/bin/dcraw_emu -w ~/Downloads/fujifilm_x_t2_01.raf

real 1m13.437s
user 1m14.630s
sys 0m0.543s

I notice the full raw decode is not using any threads. Even so, I was surprised to see the full version taking 25x more user computing time.

Any thoughts? I haven't tried debugging this to see what is going on.