Neither of those require an exponential leap: They both require linear leaps in processing power

1. Rendering an image at twice the framerate requires twice the processing power: O(n).

2. And rendering the image twice (once for each eye) also requires twice the processing power: again, O(n).

Two consecutive linear relationships isn't the same as an exponential relationship, it's O(n²).

Anyway, back to the figures: The PS3 GPU runs at 0.2 TFLOPS. Doubling the required performance gets 0.4 TFLOPS, and doubling it again gets 0.8 TFLOPS, which is still lower than the PS4's 1.84 TFLOPS processing power. Neither of those require an exponential leap: They both require linear leaps in processing power

1. Rendering an image at twice the framerate requires twice the processing power: O(n).

2. And rendering the image twice (once for each eye) also requires twice the processing power: again, O(n).

Two consecutive linear relationships isn't the same as an exponential relationship, it's O(n^{2^).}

Anyway, back to the figures: The PS3 GPU runs at 0.2 TFLOPS. Doubling the required performance gets 0.4 TFLOPS, and doubling it again gets 0.8 TFLOPS, which is still lower than the PS4's 1.84 TFLOPS processing power.