Estimating Titan X graphics card impact on performance
There are a lot of parameters which matter when using GPU's for machine learning, some of them are:


CUDA core count
Memory bandwidth (GB/s)
Memory per core (MB)
Raw Speed (MHz)
Total Memory available (GB)
Performance on 16-bit, 32-bit floating ops/sec


Tim Dettmers has an excellent (frequently updated) blog where he's compared different cards, near the end he's also given a simple speed-up comparison. Using that as a guide, it can be estimated that Titan X pascal would be upto 5 times faster than a GTX 970 for Deep Learning.