Hm that's same or less shaders than PS4 Neo.
It's the same number of shaders as a 380/280X actually. Meaning performance should be 15 - 25% better than the current 280X depending on the clocks. It will undoubtedly be far more efficient power consumption wise though.
A quick calc:
280/380X TF* - 3.5
4XX TF** - 5.5
That would indicate 57% increase in floating point performance (which nobody would believe)
*According to AMD
**According to leak