According to the latest information, NVIDIA is working on a GTX 1070 Ti in order to respond to AMD's RX Vega 56. At the moment there isn’t a lot of information on this topic that can be found, but current rumors suggest that the GTX 1070 Ti will perform almost on par with the GTX 1080.
The alleged upcoming NVIDIA graphics card should be as fast as the Vega 56 from AMD. In addition the graphics card is supposed to be equipped with 8GB of VRAM although it’s still unclear if it's going to be equipped with GDDR5 or GDDR5X memory. If NVIDIA is going to use 9Gbps GDDR5 memory, the upcoming GTX 1070 Ti could perform similar to a GTX 1080.
Earlier this year NVIDIA released an updated versions of their GTX 1060 (6GB) and 1080 GPUs, increasing the cards memory clock speeds, improving the GPUs overall performance. Perhaps NVIDIA wants to do a similar thing with the GTX 1070. According to OC3D, the upcoming GTX 1070 Ti might be also a good graphics card for miners due to the fact that the performance is similar to a GTX 1080, yet the card is more affordable.
Source:
OC3D