Absolute Power


Power-Efficient Portable Computing

This blog originally posted on the Low Power Engineering Community 9/8/11.


We’ve been examining power efficiency of iOS devices for a while now, and it’s hard not to notice the relative trajectories of mobile operating systems and more traditional PC operating systems. With the recent release of OS X Lion, Apple is moving in the direction of converging capabilities of these platforms, with the clear goal of a more unified environment coming down the line.

When I first played with the iPad and iPad2, I thought I had purchased my last laptop computer. The portability and battery life of these tablets were so compelling that surely the days of the laptop were over, and it was only a matter of time before tablets ruled the portable computing category. And sure enough, in the last couple of years, tablets have multiplied faster than rabbits. But interestingly, none have taken significant share away from the runaway success of the iPad.

Then in late 2010 came the refresh of the MacBook Air, transforming an over-priced, under-powered specialty gadget into a mainstream computing device that has breathed new life into the entire laptop category. Sure, it was still at least one generation behind in raw compute power, but as we all know by now, it’s the combination of compute power with all of the other system parameters that determines utility today, and the 2010 MBA hit the center of the target. And to top it all off, less than one year later, the July 2011 MacBook Air refresh brings latest technology to this form factor, completing the repositioning of the MBA from a “snob’s machine” to one that can satisfy 80% of the market. I got my 13” MBA a few weeks ago, and have been impressed not only with its speed (1.7GHz Core i7 with 3MB cache, 4GB memory, and 128GB flash disk), but also its power efficiency (about five to six hours of typical use.) On the “Star Trek” power efficiency test, the 13” MBA fared very well—It made it through the entire 2:06 movie at maximum brightness and consumed about 22.5 Wh of energy, nearly the same as my 2010 11” MBA at 21.35 Wh.

My biggest dilemma now is which device(s) to bring with me? My arsenal now includes the iPhone 4, iPad 2, 11” 2010 MacBook Air, and 13” 2011 MacBook Air. All are very compelling, but a few factors make the determination easy, at least for now. First, the iPhone 4 is in. It’s the one device that I ALWAYS carry with me. Small, light, and utilitarian, it’s the 21st century Swiss army knife. The dilemma is, which additional device makes the cut? I’ve already decided that Internet access is best achieved through my phone via the personal hotspot feature, so that’s a wash. The iPad 2 is a wonderful machine. It still tops the list for the most compelling portable movie-watching device. Compared with all of the other devices, the display is big, crisp and clear, with deep rich colors, and exhibits the fewest artifacts. It’s a winner, but unfortunately iOS apps still restrict serious usage for entering or editing the standard documents that we all need to access, namely those created in Microsoft Office. Sure, it’s possible to upload/convert to Google Docs and edit online, but access isn’t 100%, and the interface is still a kludge in iOS, at best. I’m convinced that storage and editing in the cloud is the way of the future, but unfortunately, we’re stuck here in the present for now.

Which leaves me with two great choices for larger-format portable computing, the 2010 11” Air, or the new 2011 13” Air. The 2011 13” Air is a fantastic machine—blazingly fast and extremely power efficient. The display is significantly bigger than the 11” version, but so is its form factor. I’ve decided that my ultimate road warrior combo is my iPhone 4 coupled with the 11” MacBook Air. Everything I need, and super portable!

From the software standpoint, being able to run standard apps is certainly a compelling feature. Note to Microsoft: Where is that iOS Office app? Or maybe the operating systems are converging even faster. I’ve tapped the screen of my Air many times in the last few months, expecting a document to open, or a Web link to be followed. Certainly there are prototypes of touchscreen laptops deep in the research facilities at Apple. Plus, the large track pad and additional interface features in Lion (MacOS 10.7) are starting to make this laptop feel a lot like a tablet!

With this many great choices out there today, I can tell that my ultimate combo probably won’t last long. A converged iMacOS or big jump in performance and apps might well nudge the iPad (3?) back into the lead. But one thing’s for sure: I haven’t purchased my last laptop!


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