It has already been known that NVIDIA will be making use of HBM (High Bandwidth Memory) in their next iteration of their graphics cards. Just last month NVIDIA had taped out their GP100 silicon on TSMC’s 16nm process. The latest reports are now saying that we should expect two GPUs coming from NVIDIA, both of which will feature HBM2.
The first GPU will use 8-Hi stacks of HBM2, while the second will only use 4-Hi stacks. Both will be based on the Pascal architecture, be 16nm, and will have a 4096-bit memory bus. The 4-Hi card will be clocked at 1 GHz and will be the more consumer-orientated card. If NVIDIA keeps their same naming it would be something like the GeForce GTX 1080. The second variation (8-Hi) will be more focused towards the professional market, think Quadro or Tesla.
If you are first hearing of x-Hi, the “x” or in this case 4 or 8 represents the number of stacked DRAM dies. NVIDIA is expected to roll out Pascal-based cards sometime in 2016.