> The annoying thing for GPU training is handling the cudNN dependency, which Google's guides are annoyingly lacking.

I've found a nice workaround for that one that does not require registration with nvidia so you can automate it:

    ML_REPO_PKG=nvidia-machine-learning-repo-ubuntu1404_4.0-2_amd64.deb
    wget http://developer.download.nvidia.com/compute/machine-learning/repos/ubuntu1404/x86_64/${ML_REPO_PKG} -O /tmp/${ML_REPO_PKG}
    sudo dpkg -i /tmp/${ML_REPO_PKG}
    rm -f /tmp/${ML_REPO_PKG}
    CUDA_REPO_PKG=cuda-repo-ubuntu1404_7.5-18_amd64.deb
    wget http://developer.download.nvidia.com/compute/cuda/repos/ubuntu1404/x86_64/${CUDA_REPO_PKG} -O /tmp/${CUDA_REPO_PKG}
    sudo dpkg -i /tmp/${CUDA_REPO_PKG}
    rm -f /tmp/${CUDA_REPO_PKG}
    apt-get update
    apt-get install libcudnn5-dev
    apt-get install libcudnn5