So I share some result with my other 970s ( more OCed) MSI_Gaming and Palit Jetstream...

Reference 970 @ 1505 MHz, tpruvot 1.8.1, maximum frequency. 20MHz more it crashes

The tolerance of the frequency could be related to the chip itself, to evaluate the overclocking headroom we should at least compare with the same miner on the same settings and VGA, with at least 3 measurements and average readings. ASIC quality 64%, so technically speaking a lower average frequency (I've got a custom liquid cooler).
With the same frequency it should be almost the same result, because of there's a gap of 86.5MHz on the core.
+15% should be 185.51 MH/s. The interesting thing it's the TDP amount on GPUz, I should test with the wattmeter with the 2 kernels because it seems that it's less stressful than tpruvot 1.8.1
You can't just throw a completely different configuration at a different benchmark and compare the two. The whole reason I asked him for a screenshot running Epsylons. I have 970s and have also ran Epsylons, it's not the same thing.