[stevenhuang]

I think what we're seeing is just an increase in the power envelope: more power for more performance.

Efficiency should be better than previous gens, at least this was the case for the CPUs I looked at (looking at their power efficiency ratings at full TDP they're hard to tell).

Marginal efficiency is lower when the power envelope is expanded to make these higher performance numbers achievable.

I'd wager that performance matched, these "power hungry" current gen GPUs/CPUs would show better efficiency than previous gens.