Just gonna copy and paste this because I feel like this issue is going to keep popping up:
The A10X is -slightly- slower multi core, but it's GPU OWNS THE A11. With an a11 graphics on the new iPad pros would be around the same as the first generation pros. Apple has been making strides but they obviously don't got the in house gpu's fully down. It's a reason why the new Apple TV used the a10x, it needs the gpu performance over the slight processor improvement.
http://browser.geekbench.com/ios-benchmarks
Apple says the graphics (metal) is 30% better than the a10, that leaves it far behind the power of the a10x, and around on par with the first generation iPad pros.
Also the above is most likely correct, the a11 can use all 6 of its cores to provide a score -slightly- above the a10x, but you have to remember, 4 of these on the a11 are designed as power saving, how long will they really be active, and what kind of real world scenario actually gets it to switch from the 4 energy efficient, to the 2 power cores, then up to all 6? With a10x it's either in power saving or performance mode, there will be no middle state where you only have some of the performance.