Adding GPUs seems a no-brainer in retrospect. Have top500 institutions outside China been trying this approach?

Except one thing. Until recently GPUs have only done single-precision calculations. Double precisions has been added with the latest architectures but double is, I believe, still very slow. So this means that single precision results are sufficient for the top500 tests as well as the particular applications (in the Tianhe’s case: weather and oil exploration)?