TBH TFLOPs is a useless metric for gaming performance, much like how clock speeds are useless for determining CPU performance.
TFLOPs should only ever be used to compare hardware from the same generation, as performance per clock can change wildly.
One other thing to note that on the Nvidia side they use base/boost clock to get their TFLOP numbers. When was the last time you have seen a Nvidia GPU clock anywhere near their base speeds? GPU Boost 3 ensures that clocks, in reality, are much higher, so the real TFLOP numbers should also be higher.