Not entirely true. For good utilization you need both GPU/TPU ops to be fast (written in C), but that won’t get you far if your input pipeline (possibly written in python) is slow. I could imagine if all the TF calls work in PyPy, that it would help with throughout by speeding up the input pipeline and keeping the GPU/TPU saturated more effectively. One solution is to write everything to TFRecords, but for experimentation that’s kinda annoying.