You should be careful on the memory bandwidth. The more recent xeons (2011v3, ddr4 2133) are rated 68 GB/s per socket. That is 136GB/s in a dual socket. But, w

You should be careful on the memory bandwidth. The more recent xeons (2011v3, ddr4 2133) are rated 68 GB/s per socket. That is 136GB/s in a dual socket. But, what I really came here to say, is that POWER8 has nearly twice the single thread memory bandwidth available. From some of my tests a single thread can access ~40GB/sec of bandwidth vs the intel at ~20GB/sec. But this doesn't translate into clear cut wins even on codes which at first pass appear to be bandwidth limited. Mostly because the processor cores themselves are about 1/2 the speed in tight loopy code (think nbench) running out of cache. So, in our in house benchmarks the POWER ran anywhere from 75% as fast to roughly as fast. Only on a few tests did it actually manage to best the E5 xeon we were testing it against, and then never by more than 150%. Plus, the dynamic thread controls are cool, but beyond 4 threads/core I could never actually improve performance, and beyond 2x it was major diminishing returns.