I remember reading somewhere that PHP 7 outperforms Ruby and Python 3 in some 'speed tests' and Mandelbrot fractal generation. I really love the optimizations they did on PHP 7 and Rasmus briefly talked about even more optimizations coming to 7.3. They will reduce the number of instructions being performed by scanning non-used code first in MUCH MUCH more places than they already do. Basically, if you initialize a variable that's never used, or if you loop N times to do basically no logic relevant to the rest of the scope, no instruction will be executed. Basically, PHP 7 is twice as fast as 5.6. Amazing!
I don't have any real benchmarking evidences, just wanted to be in a conversation! :D