Hacker News Reader

That's an older paper, but yes there have been more than one independent study showing 25x boost in terms of energy efficiency. See Ericsson FFT paper, OpenWall bcrypt paper, and others at parallella.org/publications.

The Epiphany gains are certainly only achievable for massively pipelinable or embarrassingly parallel operations with very little intermediate state (e.g. streaming data, neural software, etc), not for random access large memory footprint crunching like the Xeon. There simply isn't the per-core memory (64KB), or external memory bandwidth, to go around otherwise.

Xeon, Power, etc are kind of power pigs anyway, though they've got a lot of absolute oomph to show for it.

That's not unreasonable.

I should clarify:. Presumably the parallella's RISC does away with a lot of the superscalar features of the x86 which are embedded in the xeon phi's

One way to think about it is that things like branch prediction and speculative and out of order execution are like real-time JITting of your code.

Not having that silicon can make things way more efficient.