Apple has opened up WWDC 2013 with an announcement of a new MacBook Air models. They look the same, they cost just about the same and in many ways, they are the same.

But they're not. Phil Schiller, Apple's senior VP of worldwide marketing, said: "MacBook Air is the industry leader for thin and light notebooks, and now with longer battery life, we've set the bar even higher."

But how does it set the bar higher? We've quickly broken it down, so you can see exactly what the difference is.

1. Intel inside

The new MacBook Air (2013) comes with the fourth generation of Intel Core processor. Known colloquially as Haswell, Intel has focused on improving battery performance, so the new MacBook Air 11-inch will give you 9 hours of "wireless web", compared to 5 of the 2012 model. The 13-inch MacBook Air will see you through 12 hours, compared to 7 hours previously.

2. Store more for less

The 2013 MacBook Air 11-inch now starts at 128GB of internal storage, compared to 64GB previously. That's a solid-state drive, naturally. Now both the 11 and 13-inch models have the options of 128, 256 and 512GB. Seeing as the 11-inch model is the same starting price at £849, you get double the storage for nothing. The 13-inch model with 128GB is now £949, so the starting price is actually £50 less than the last-gen Air.

3. Faster graphics

The MacBook Air uses the Intel integrated graphics solution. With a new Intel processor, comes new graphics, the Intel HD Graphics 5000. Apple says this is 40 per cent faster, giving you better performance on graphics-intensive tasks. Not only that, but Apple claims the storage is 45 per cent faster too.

4. Faster data

The 2012 MacBook Air uses IEEE 802.11n Wi-Fi, but now steps up to 802.11ac in the new models. This is the latest Wi-Fi protocol allowing for faster transfer of data and longer Wi-Fi range. You'll have to have a compatible router to support the standard on your network, and Apple has updated the AirPort Extreme and Time Capsule for just that reason. Other routers are available, but check the specs, as this new Wi-Fi protocol is still pretty rare.

5. Dual mics

That's right, a minor detail, but Apple has replaced the omnidirectional mic of the 2012 MacBook Air, with a dual mic arrangement in the 2013 MacBook Air. This will let the new MacBook Air cut down on background noise, so dictation or video calling should sound better than ever before.

The rest is the same

So that's it. A package of changes that, from the outside, make little physical different to the new MacBook Air. But inside, the new processor and graphics, as well as faster storage, mean that the new Air will outperform the old. And seeing as the 2013 models look like better value for money than the 2012 models, if you're in the market for a new MacBook Air, you should be feeling pretty smug.

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