True - I am considering the 3.7 to 4GHz i7 processors as well because of higher clock speed.

Some things that are enticing towards the Phi, are 1) 16GB on chip MCDRAM - that is a lot of cache! 2) I can get a copy of Intel Parallel Studio XE compiler and compile Lua and Torch from source code, thus making them use more cores on Phi.

I have reached out to Intel AI developers and NVidia cuDNN team to ask their take on it. Let's see what they advise.