The folks over at iFixit are hard at work dissecting the newly announced/soon-to-be-available iPhone 4S. We've already gone over performance expectations as well as provided a high level hardware analysis, but with a tour inside the smartphone we're able to confirm a few suspicions. First is the Qualcomm MDM6610 baseband, a slightly different part from the MDM6600 that we had theorized earlier. There isn't a whole lot of documentation out on the 6610 but we're digging.

The second confirmation iFixit's teardown gives us is the size of the A5's on-package memory: 512MB. A quick look at the image above yields the Samsung part number: K3PE4E400B-XGC1. Each highlighted E4 refers to a separate 2Gb LPDDR2 die. The A5 features a dual-channel LPDDR2 memory interface, thus requiring two 32-bit die to fully populate both channels. The final two characters in the part number (C1) refer to the DRAM's clock period, in this case 2.5ns which indicates a 400MHz clock frequency (F=1/T). My assumption here is Samsung's part number is actually referring to clock frequency and not data rate, implying there are a pair of LPDDR2-800 die in the PoP stack. It's not entirely uncommon to run memory at speeds lower than they are rated for, a practice we've seen in graphics memory in particular for as long as I can remember, so I wouldn't take this as proof that Apple is running at full LPDDR2-800 speeds.

At a high level there aren't any surprises here, the A5 on the iPhone 4S is virtually identical to what was used in the iPad 2 - although running at a lower clock speed and likely a lower voltage as well. Many are surprised by the inclusion of only 512MB of RAM on the A5's PoP stack, however since most apps not in use are kept out of memory to begin with having more memory doesn't actually buy you a whole lot of performance. There are also potential battery life concerns with larger DRAMs: more room for apps to remain resident in memory leaves more DRAM cells to refresh, which impacts power consumption (although eventually Apple will have to cross this bridge, likely with the next process node transistion). I suspect the biggest issue created by not outfitting the iPhone 4S with more DRAM is limiting game developers to smaller levels, fewer unique textures, etc...

My real question is what comes next. Will we see a 28/32nm A5 used in the iPad 3 in 1H 2012 or will Apple continue to push the envelope and embrace a 28/32nm A6 with a pair of Cortex A15s in the second half? The latter is what I'd like to see, although it would effectively move all of the flagship iOS product launches to a fall ordeal.

Source: iFixit

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  • choirbass - Friday, October 14, 2011 - link

    on second thought, youd still have some noticeable pixelation by only doubling it, but it would be at least an improvement in any case. Reply
  • choirbass - Friday, October 14, 2011 - link

    hm,. ok, yeah... ~2560x2048 is about whats necessary @ 9.7" to be near 330ppi (its a couple pixels above). not sure thats gonna happen, lol :P Reply
  • 00DC2TW - Friday, October 14, 2011 - link

    Anyone know if the MDM6610 will support tmobile 3G USA? Reply
  • Dennis Travis - Sunday, October 16, 2011 - link

    Anand, are you and Brian planning a full on review of the 4s like you guys did with the 4? Yours was the best and more informative review on the internet. I hope you do. Reply
  • Rizi - Tuesday, July 17, 2012 - link

    When Apple announced the new Siri software for the <a href="http://cellocean.com/iphone-4s-specifications-2210... 4s</a> it was easy to just dismiss it as another company trying to get on board with the voice recognition gimmick we've seen companies trying to make work for years. But there are a couple of things to remember here: firstly, this is Apple, a brand that will always make something seem cool and work pretty well. And secondly, it's not a technology that it's had to develop fully in house, with the company buying voice recognition development app-maker Siri. We've played with some pretty advanced voice recognition software on the likes of the Samsung Galaxy S2, so we've also taken a look to see how the same command is registered on both phones. Long pressing the home button will result in the Siri voic icon popping up - or alternatively, you can set the iPhone 4S to activate the service when you hold the phone up to your ear in standby mode, so you don't look as ridiculous when talking to your handset. From there, you've got quite a range of things you can achieve with speech alone, be it sending a message, playing a song (or even a playlist), setting the alarm, creating a reminder... we were very impressed with the range of options on offer. And the system is quick too - where with many other phones you have to open up the voice recognition function (often in a long winded way) and then wait for the beep to speak, Siri opens up in around a couple of seconds from anywhere in the phone. The voice recognition is pretty darn good too - we were straight away impressed with how many phrases it managed to get right on the first go, including some pretty obscure bits and pieces of speech. You do have to pronounce your words a little more clinically than you might do normally, but even garbled speech comes through pretty well. To put a number on it: we went through the list of functions Siri offers, and found that around one in three or four attempts went awry, which is miles better than the one in two we encounter on most other phones. However, before we get into the comparison, we should say this about Siri in the UK - the full range of services aren't available, and that's a real shame. This means you can't ask where the nearest McDonald's or petrol station is, a feature that's been talked up in the US. We do have high hopes that the same features will eventually be enabled in the UK, as it's just a matter of licensing the information and incorporating it into the system, but it will be annoying for a number of users to see that Siri comes back with 'I cannot do that' time and time again for cool functionality. But what it does do well is work out the context of what you're saying, something that most other voice recognition software fails to do. So if you say 'Tell Andy his hair looks amazing today' it will work out that you'll want to tell him by message, rather than asking what method you'd prefer to speak to him. Messaging isn't as straightforward as we'd like though, as using the 'Send message' command to a person in your address book will result in you being asked whether you'd like to do it using the phone number or email address - and there's no way to set a personalized choice. Reply

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