According to the rumor mill, Pascal taped out on a 16nm process and the card will reportedly feature as much as 16GB of HBM2 for the consumer parts, and as much as 32GB HBM2 for the professional versions.
The design of the board is very similar to the Fiji-powered cards from AMD, as NVIDIA's Pascal chip is on a similar interposer to AMD. It looks slightly bigger, but we should expect the Pascal-powered cards to blow the doors off of the Fiji-powered cards from AMD. We will see DirectX 12 support, around 17 billion transistors, a 4096-bit memory interface, and so much more.