This version has 1280 CUDA cores, which is the full core count of the GP1060, but it has a 160-bit instead of a 192-bit memory bus. The GeForce GTX 1060 5GB is primarily intended for internet cafes and will probably be hard to find outside Asia.
The extra memory should improve 1080p gaming performance, a use case where the 3GB version lacks a little oomph.