> 20--30% sounds as the right efficiency numbers at that level. Precisely 90W
> ARM SoCs are providing around 80--90% of performance of 140W Haswell Xeons.

Seriously dude. What 90W ARM server chip is providing performance to customers?

Let me remind you that server chips must be implemented in silicon, not power point to provide value to customers.

And I'm quite willing to bet that no ARM server design in the next 2-3 years will provide 80% of the performance of the highest bin Xeon. If they are lucky, they might get to the low-end territory. They probably also won't have as much memory capacity and generally be inferior across a number of dimensions.

DK