Earlier quoted context omitted.
That's why you scroll down the page to the cost comparison, which places it on a more even keel. They do also compare float16 on Volta. Physical packaging is irrelevant -- what matters is dollars to convergence and time to convergence. (I'm obviously biased - I helped with parts of the cloud-side of cloud TPU - but I presume this comment stands on its own. :-)
To be clear, I had read the whole post, I was just being terse since the emphasis seemed to be so heavily on an apples to bananas comparison (I believe 100% of the results cited in the prose, many in bold, are with mismatched precision and batch size), with minimal articulation of the many axes of nuance here. Precision isn't defined at all in the LSTM case, and could easily be the cause of the failure of the TPU run…
Our intention is really to provide a sound comparison. I think we agree that these kinds of comparisons can be hard given the constraints (e.g., lack of available technical information on TPUv2 or public implementations of optimized models for certain architectures). As I stated elsewhere, we are collecting all of the feedback and will run additional experiments.
If you know of an implementation of a mixed-precision/fp16 model that you'd like to see results for, please let us know! I may also reach out directly to you for that if you don't mind.