https://wccftech.com/nvidia-geforce-gtx-1070-gddr5x-memory/

It looks like we will soon be looking at a new variant of the GeForce GTX 1070 graphics card with a slightly different memory design. According to the latest report from Videocardz, an NVIDIA board partner has leaked out their own upcoming GTX 1070 model which supports GDDR5X memory.

This was going to happen eventually as NVIDIA board partners were shipping GeForce GTX 1060 models with GDDR5X memory for a while now. The GeForce GTX 1070 was the only GP104 which was still using the GDDR5 memory but that isn’t the case anymore.