The R7 360 consumed considerably more power than the GTX 750 Ti -- 36% more when testing with Metro: Last Light. Despite that, the R7 370 actually consumed 12% less power than the GTX 950 in an interesting twist.
The R9 380 might have been on average 5% faster than the GTX 960 and up to 13% faster in Dragon Age: Inquisition, but it also consumed 15% more power. Likewise, the R9 390 was on average just 3% faster than the GTX 970 but it used 8% more power.
The R9 390X consumed 15% more power than the GTX 980, which is surprising since it was slightly slower on average. A similar situation is found when comparing the Fury X and GTX 980 Ti, overall the Fury X was slightly slower but needed 7% more power.