In raw power x64 is still the king, has always been.

You can skew things by looking only at single core performance (where apples most expensive cpus might win because of their strategy of having fewer but more powerful cores + memory latency gains are much more visible with only one core).

With that said, things are changing in the PC landscape and some extremely powerful and power efficient ARM designs are coming soon. We have already seen a small glimpse of that with MediaTek.