Editors' note: This article was originally published June 27, 2013, and was updated August 22, 2013, to reflect that many more systems are now available with Intel's latest processors, with still more to come later this year.
Before swiping your credit card on a new ultrabook, all-in-one, or convertible, you're going to want to dive a little deeper into the spec sheets. That's because the latest Intel CPU upgrade, introduced in June and code named Haswell (but officially known as "fourth-generation Core i series") offers significant battery life improvements in the laptops we've tested so far. So, unlike the more ho-hum Intel updates we've seen in years past, there's a real-world payoff in seeking out a Haswell-equipped laptop.
But, many popular laptops, such as the Lenovo Yoga 13 and Apple MacBook Pro with Retina Display, still use third-generation Intel CPUs, with no official upgrade plans yet announced. If better battery life isn't a big concern, for example if you're going for a desktop PC, or if you have a "desktop replacement" laptop that you don't tend to disconnect from the power cord, this could work in your favor, and you could score a nice discount as more pre-Haswell PCs make their way to the discount bin.
How do you tell which is which? That's the tricky part.
The current laptop landscape
As we move into the Haswell era, the market is in flux. Many "new" laptops and hybrids, such as the Lenovo IdeaPad Yoga 11S or the Toshiba Kirabook, all still ship with processors from Intel's third-generation Core i series, the same parts that have been found in most PCs since spring 2012. On the bright side, some popular systems, including the Acer Aspire S7, have added Haswell parts.
Normally this wouldn't be a big deal, because any current laptop will have more than enough processing power for everyday tasks, such as Web surfing, HD video playback, social media networking, and working on basic office documents. For that reason, in years past, having the latest and greatest processors wasn't especially high on my priorities list. Frankly, the average consumer wouldn't feel much of a difference in surfing the Web on a laptop with a budget-minded Intel Core i3 versus one with a high-end Core i7.
But with a growing number of Haswell PCs (and Macs) tested, the battery life results from them so far has been very impressive. The Haswell-equipped PCs also offer Intel's better integrated graphics, either the HD 5000, HD 4600, or HD 4400, rather than the now-outdated Intel HD 4000 graphics found in third-gen Core i-series systems.
Case in point: the 2012 version of Apple's 13-inch MacBook Air ran for 7 hours and 27 minutes in our video playback battery drain test. The 2013 version of the 13-inch Air, with a Haswell CPU, blows that out of the water, with an astonishing 14 hours and 25 minutes on the same test. Sony's Haswell-powered Vaio Pro 13 ran for nearly 9 hours, and even the gaming-oriented Razer Blade, ran for more than 7 hours.
How to choose
The natural question this raises is: should you hold off on buying a particular PC if it still has a third-generation Intel Core i-series processor and wait for the Haswell version? Some popular systems, including the Lenovo Yoga line, the Microsoft Surface Pro, and Apple's MacBook Pro have not publicly announced street date for updated versions with the newest Intel CPUs.
I suggest approaching with caution, although I'm not ruling out buying a non-Haswell system altogether. Below are some guidelines that represent my current thinking on the subject; feel free to add your own suggestions and ideas in the comments section below.
Desktops and larger laptops: Buy now
Considering the modest gains in actual application performance (including the HD 5000 graphics), if you're holding off for performance reasons, don't. For a traditional desktop or all-in-one with no battery, the last-gen processor isn't a big deal. The same goes, to a lesser extent, for 15-inch and larger laptops, which by their nature spend most of their time tethered to a desk and power outlet. On the bright side, some gaming laptops, such as the Alienware 14 and Toshiba Qosmio X75, have already moved to Haswell.
Ultrabook-style systems: Seek out a Haswell version
Some of the best ultrathin laptops, namely the Apple MacBook Air, Sony's new Vaio Pro (both of which are available in 11- and 13-inch models), and Acer's Aspire S7 now have the new Intel CPUs. Battery life on these is amazing, and I'd be hard-pressed to buy a premium ultrabook (or faux-trabook) with shorter non-Haswell battery life. It would certainly be painful to spend more than $1,600 on a Toshiba Kirabook or Lenovo Helix and not get the latest processors (and the resulting boost in battery life).
Budget shoppers: Wait if you can, or seek out bargains if you can't
Some of our favorite reasonably priced laptops, such as the Dell Inspiron 14z and Sony's Vaio Fit 14, are not available with fourth-gen Intel Core i-series CPUs yet, nor is there an estimated date for them. The new Core i3 CPUs for budget and midprice systems are the last item on Intel's priority list (the highest-end quad-core Core i7 chips came out first, followed by Core i5 versions), and more-modest battery life expectations are built into buying a sub-$800 laptop. That said, we're already seeing some good deals on pre-Haswell PCs, as retailers and manufacturers begin blowing out inventory to make room for those new Haswell models. Keep an eye on those Sunday newspaper circulars and Internet deals.
Tablet/hybrids: Wait for Haswell
Tablets are designed for all-day on-the-go use, but to date, many Windows models -- from the Lenovo Yoga to the Microsoft Surface Pro -- haven't yet hit that battery life sweet spot. Well, it's time to stop compromising. Every Windows 8 device that's either a slate-style tablet or laptop/tablet hybrid could benefit from the extended battery life offered by Haswell. (That also goes for Intel's next-gen Atom CPU, dubbed Bay Trail -- also due soon.) The 14-hour battery life on the new MacBook Air proves it: it's possible to get much better battery life on tablets than we're getting now, and we should demand it. In other words, if you like the look and feel of a current Windows tablet, hold out for the Haswell version. Fortunately, some hybrids, such as the Dell XPS 12, are now shipping with Haswell CPUs.
Bonus advice: Don't worry about Windows 8.1 or Mac OS X 10.9 Mavericks
Savvy tech shoppers know that Microsoft and Apple are both updating their operating systems before the end of the year, to Windows 8.1 (due October 17) and Mac OS X 10.9 Mavericks. The good news is that the Microsoft upgrade will be free (for existing Windows 8 users), and the Mac upgrade is likely to be very cheap (Apple hasn't announced dates or pricing, but the last few Mac versions have been only $20). Any computer running the current OSes should be easily upgradable to the forthcoming versions; there's no reason to wait for them to be released before buying.