CPU performance update

@jcjohnson hi, really nice benchmark!

I am working on torch optimization for intel platforms, Xeon and Xeon Phi. Our optimized version is much faster than original torch cpu backend and we are trying to upstream. https://github.com/intel/torch.

About the saying "The Pascal Titan X with cuDNN is 49x to 74x faster than dual Xeon E5-2630 v3 CPUs." this is somehow missleading :(

This is because a)pascal is the latest generation of gpu while Xeon E5 v3 is about 4 years ago b)our intel-torch yields much faster performance that is competitive to GPU.

We are happy to update the benchmark performance on intel latest hardware platforms, Xeon E5-2699v4, Xeon Phi 7250 (KNL) and also the upcoming platforms (SKL/KNM).

Could you please update these numbers once we finished? :)

Start by reviewing the existing benchmark setup in cnn-benchmarks and the linked Intel torch implementation. Confirm the updated results on Xeon E5-2699v4, Xeon Phi 7250, and the mentioned upcoming platforms, then update the benchmark numbers so the comparison reflects the newer Intel hardware.

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