Apple's MacBook Air line is now rumored for a summer refresh, leveraging Intel's next-generation Sandy Bridge architecture. An anonymous source "familiar with Apple's plans" told CNET that the update would come in June of this year.

Intel officially launched Sandy Bridge, which combines a CPU with an integrated memory controller and integrated GPU on the same silicon die, earlier this year. Some Sandy Bridge processors have already been shipping to vendors who plan to release desktops and laptops that use the new chips soon, though some products will be delayed a few weeks due to a flaw discovered in some 6-series controller chips required by Sandy Bridge processors.

The June timeframe would roughly coincide with an expected release of ultra-low voltage Sandy Bridge variants later this year, which Apple would require for a MacBook Air. We noted in our review of the MacBook Air that it was unfortunate that Apple felt compelled to stick with older-generation Core2 Duo processors for its ultra-portable line due to limitations in graphics performance for Intel's Arrandale-class mobile processors, as well as size and thermal design constraints. A Sandy Bridge update would bring massive CPU performance improvements to Apple's most diminutive laptops with little change in power requirements.

We discussed last December why Apple may ultimately dump NVIDIA GPUs that the company has relied on for the MacBook Air line in order to gain Sandy Bridge CPU performance. While Sandy Bridge's IGP is not a particularly modern design, it does benefit from being directly connected to the CPU on the same die. Consequently, its performance is believed to be on par with the IGP included in the NVIDIA 320M controller that Apple currently uses. Also, Intel has been working on bringing OpenCL-compatibility—an important technology for Apple—to Sandy Bridge via drivers for the individual CPU cores. And finally, NVIDIA has flatly stated that the 320M is the end of the line for the company's Intel-compatible chipsets.

The June timing also makes sense for a couple other reasons. Before the extra long 16-month wait for the most recent MacBook Air update last fall, the first couple update cycles were about 8 to 9 months. (The original Air was launched at the beginning of 2008. The first update came in October 2008, and the second in June 2009.) Apple could potentially use a keynote presentation at WWDC, which is expected to occur in early June, to announce the next update.

As far as Apple's other portables are concerned, CNET noted that updated MacBook Pros have been rumored for a March release, perhaps announced alongside updated iPads. However, that release could potentially be affected by the delay caused by the flawed Intel controllers. It should be noted that the same size and thermal constraints that apply to the MacBook Air also apply to Apple's 13" MacBook and 13" MacBook Pro. If Apple does announce updates to those models this spring, it may give us an early look at what the internals of a Sandy Bridge-based MacBook Air will look like.