I've posted before about the potential use of ARM-designed chips in servers as an energy efficiency play. This article from The Economist focuses on the potential market battle between Intel and the ARM cluster of companies, noting that energy efficiency is the basis of the competition.
In a nutshell, ARM chips dominate mobile electronics applications, which of course means that energy efficiency is a prime design attribute (to maximize battery life). Intel dominates in desktops, laptops, and data center gear, and their processors bring awesome computing capability to bear at increasing energy efficiencies. (Disclosure: Intel is one of my clients.)
It's been posited that ARM-like designs would be applicable to Intel's markets on the basis of energy efficiency - a server running ARM chip sets could use as little as a tenth of the power of an Intel-based model, according to HP (HP has a project to develop ARM-based servers called "Moonshot"). ARM chips might also be suitable for PCs - certainly in the laptop, tablet, and new "ultrabook" categories.
The article points out many of the barriers that would prevent one side from gaining traction in the other's turf: the PC market is stagnant (so why bother), Intel has developed the Atom processor which has efficiency on a par with comparable ARM products, ARM designs likely lack the performance needed for server workloads, and the whole issue of whether software companies and other industry players will support new platforms.
I'll raise just two issues.
First, it has always appeared to me that issue of server energy efficiency is mooted by the incredibly low average utilization rates in most applications. Even the best internet-focused companies with largely homogeneous workloads only report rates in the twenty percent range, and enterprise users are lucky to see rates over ten percent. So efficient power supplies or even comparative advantages in processor efficiency simply don't make the difference that improved utilization would.
Second, the PC market is relatively stagnant, but there are tremendous opportunities to drive efficiency through refresh and power management. The latest generation of Intel processors are far more efficient than cores made just three years ago, and coupled with power management, desktops use just a little more energy than a late generation laptop.
Which is why I counsel utilities to promote server virtualization and consolidation and desktop power management as their primary programs in these markets. Yes, there are discussions at some utilities about designing programs that reward the purchase of premium efficiency desktops and servers, but that will drive marginal energy savings compared to these two measures.
As to the ARM/Intel foray - battling over energy efficiency is a great thing!