According to previous updates, the production chips would have have greater efficiency:
Normal Mode:
0.7v vdd
6gh/s per chip
0.343w/g on chip
And looks like real performance of samples is better than predicted:
...
6.4GH/s | 0.2363W/G
6.8GH/s | 0.2439W/G
7.2GH/s | 0.2495W/G
...