WCCF Tech picked up some details about NVIDIA's GP106 GPU (GeForce GTX 1060) at shipping manifest website Zauba. It appears the GeForce GTX 1060 has a 256-bit memory bus, double as much as its predecessor:
The GP106 will be using high density GDDR5 (256MX32 configuration). Since the bus width is 256-bits, we are looking at either 4GB or 8GB of vRAM. I would like to point out here that the entry only mentions the GP106 GPU, so the information contained in the manifest can pertain to either the GTX 1060 or the GTX 1060 Ti. However, I believe it is more likely that we are talking about the former, considering Nvidia’s historical trend with the “Ti” nomenclature which usually tend to land after the vanilla offering.
According to earlier rumors, the GTX 1060 has a Fall 2016 launch date.