AMD's cards are highly overclocked when they go on sale. Whereas Nvidia's cards are not OCed much. You can see the benchmarks between 780, 770, r9 290x, 290, and r9 280x, they're performing closely to the competition but the AMD cards are cheaper. But Linus techtips also showed that when you OC to the wall the nvidia cards, it easily beats the amd cards. So that's how nvidia would keep up with AMD. I hope that answers your question.