iPad 4: the clues from the iPhone 5

Apple's new iPhone 5 isn't just a smartphone: it offers spooky glimpses into the future of the iPad from beneath an unconvincing wig.

Okay, not really, but given the very close relationship between iPhone and iPad, we can use Apple's latest invention to predict some of the key features of the iPad 4. What does the iPhone 5 reveal about the next version of the iconic iPad?

You're going to need a different dock

The iPhone 5 said goodbye to the dock connector in favour of the smaller, double-sided, expensive-cable Lightning connector, and while that means easier connections and more internal room for components it also means that existing Dock-connecting accessories will need pricey Lightning-to-Dock adaptors, pricey Lightning-to-USB cables or pricey replacements. If you're buying accessories that you intend to use with future iPads, iPhones or iPod touches, think wireless and buy accordingly.

The iPad 4 will have a better battery

The iPhone 5's battery runs at a slightly higher voltage than the iPhone 4S's: it's a 1,440mAh, 3.8-volt battery compared to the 1,432mAh, 3.7-volt battery in the 4S, delivering 5.5 watts per hour compared to the 5.25 watts per hour of its predecessor. That doesn't sound particularly interesting, but it does mean that in conjunction with improved power management, the battery delivers more power without sacrificing battery life or taking up significantly more room. For the iPad, Apple may decide that thin is very much in.

The iPad 4 will have a better, thinner screen, but probably not a bigger one

The new iPad's screen is a great thing, but the iPhone 5's is better: over at Anandtech, Chris Heinonen explains what he describes as a "quantum leap" over the iPhone 4 display. It's not the number of pixels that matters, but the contrast, light output and "astonishing" colour performance, and while the gap between iPhone 5 and new iPad isn't as big as the one between iPhones 5 and 4, the phone's display is still marginally better.

Such a display wouldn't just make the iPad 4 even nicer to look at. It would help reduce thickness and weight too, because the iPhone 5's display uses in-cell touch technology that uses embedded touch sensors rather than a separate digitiser. That means thinner displays, but it also means a headache for manufacturers: reports indicate that they're currently having problems making four-inch ones, let alone 9.7-inch ones. Adding such panels to the iPad 4, then, could be a big challenge - and by big challenge we mean enormous pain in the arse.

Could a longer iPad be in the works? Despite the rumours, we're not convinced: the current iPad and rumoured iPad mini are 4:3 devices, an aspect ratio that works really well for all kinds of content from ebooks to apps. Apple might change it, but other than watching movies - something Apple would like you to do on an Apple TV - we're struggling to think of any good reasons why they should.

The iPad 4 will have 4G. Proper 4G, not you-can't-get-it 4G

The new iPad also offered a WiFi + 4G version, but Apple was forced to change that to "WiFi + cellular" on the grounds that (a) the UK doesn't have 4G and (b) the frequencies the new iPad expects aren't the ones the UK will end up using. The iPhone 5, however, supports the same 4G LTE that Everything Everywhere is starting to roll out, and we'd expect future models to support the UK's other LTE bands when services launch next year. A UK iPad that's 4G-friendly is inevitable.

The iPad 4 will have a different form factor

Getting shot of the Dock enabled Apple to make a much thinner iPhone, and while we don't expect the iPad mini or imminent Tweaked New iPad to change the form factor when they swap Dock for Lightning, the iPad 4 could bring in a redesign: the current one is rather reminiscent of the iPhone 3GS, and its big-bevelled back is partly to disguise its size. A thinner display, thinner Dock replacement and thinner battery could mean - you've guessed it - a thinner iPad.

The iPad 4's processor will be an A6, ish

The iPhone 5 comes with Apple's own A6 processor, and analysts predict a new one every two years - but the iPad's on a yearly update cycle, so it's not going to be rocking an A7. History's likely to repeat here: where the iPhone 4S and iPad 2 got an A5 processor, the new iPad got the A5X, a faster iteration of the A5 with a quad-core GPU; if an A7 isn't doable in time, expect Apple to beef up the A6's graphics performance and stick an X on the end.

The iPad 4 will be a disaster and Apple is doomed

Cocking up Maps hasn't helped, of course, but with the iPhone 5 Apple's experienced a blizzard of bad publicity: in some cases you'd think Apple had released a phone that was just a piece of cardboard with a screen drawn on it in biro. Apple has gone from underdog to top dog, and that means a lot of people are waiting for it to fail. The original iPad created a whole new market; if the iPad 4 merely turns out to be a better version of what we've already got, expect a chorus of disappointment and disapproval.