The Impact of Larger Memory

Apple doubled memory capacity on the new iPad to 1GB, marking the first time in recent history that Apple's flagship product offers a similar amount of memory to the current crop of high-end Android devices. Apple's iOS can do a relatively good job with limited system memory as it will conservatively unload applications from memory in the event that it needs to free up more space. iOS does not support paging to flash, making DRAM size a hard limit for developers looking to really push the platform.

Apple has always been conservative on DRAM sizing because it's a great way of reducing the BOM (Bill of Materials) cost. If Apple can make up for having less DRAM by being more aggressive in software (read: kicking apps out of memory), it's a tradeoff that makes sense. It's really Apple's foray into gaming that has added pressure to increase memory sizes.

With the move to the Retina Display, the amount of memory needed to store a single frame increases by 4x—from 3MB to 12MB. Assuming two buffered frames you're looking at 24MB of RAM just to smoothly display what you're seeing on the screen.

The bigger problem isn't the frame buffer, but rather all of the other data you need (e.g. level data, textures, etc...). The higher the screen resolution, the more important it is to have higher quality assets in your game. Texture compression can go a long way, but at some point there's simply more data to deal with as game complexity increases. It's not just about the increase in resolution either. As GPU horsepower increases, so will the complexity of what game developers try to build.

While the frame buffer size increased thanks to the Retina Display, total system memory increased by a much larger amount. With 1GB of memory, game developers are now less constrained.

A more immediate benefit is apps and web pages will remain resident in memory longer as you open open up and switch to other apps. For example, on the iPad 2 if I open four tabs in Safari (AT, Engadget, Reddit, and Tech Report), open iPhoto, run Infinity Blade 2 and GTA 3, switching between the latter two will always require a full game reload (as in you see the intro and everything before you pick up where you left off). On the new iPad, with the same setup, I can switch between Infinity Blade 2 and GTA 3 and automatically resume where I last left off thanks to the extra DRAM. You can still create a scenario where even 1GB isn't enough, it's just that the limit is now higher than it was on the iPad 2.

A Word on Packaging & Looking Forward GPU Performance
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  • name99 - Friday, March 30, 2012 - link

    Just to clarify, this is NOT some Apple proprietary thing. The Apple ports are following the USB charging spec. This is an optional part of the spec, but any other manufacturer is also welcome to follow it --- if they care about the user experience.
  • darkcrayon - Thursday, March 29, 2012 - link

    All recent Macs (last 2-3 years) can supply additional power via their USB ports which is enough to charge an iPad that's turned on (though probably not if it's working very hard doing something). Most non-Mac computer USB ports can only deliver the standard amount of USB power, which is why you're seeing this.

    Your Lenovo *should* still recharge the iPad if the iPad is locked and sleeping, though it will do so very slowly.
  • dagamer34 - Friday, March 30, 2012 - link

    I did the calculations and it would take about 21 hours to recharge an iPad 3 on a normal non-fast charging USB port from dead to 100%. Keep in mind, we're talking about a battery that's larger in capacity than the 11" MacBook Air.
  • snoozemode - Thursday, March 29, 2012 - link

    http://www.qualcomm.com/media/documents/files/snap...
  • Aenean144 - Thursday, March 29, 2012 - link

    Anandtech: "iPhoto is a very tangible example of where Apple could have benefitted from having four CPU cores on A5X"

    Is iPhoto really a kind of app that can actually take advantage of 2 cores? If there are batch image processing type functionality, certainly, though I don't know if iPhoto for iOS has this type of functionality. The slowness could just be from a 1.0 product and further tuning and refinement will fix it.

    I'm typically highly skeptical of the generic "if the app is multithreaded, it can make use of all of the cores" line of thought. Basically all of the threads, save one, are typically just waiting on user input.
  • Anand Lal Shimpi - Thursday, March 29, 2012 - link

    It very well could be that iOS iPhoto isn't well written, but in using the editing tools I can typically use 60 - 95% of the A5X's two hardware threads. Two more cores, at the bare minimum, would improve UI responsiveness as it gives the scheduler another, lightly scheduled core to target.

    Alternatively, a 50% increase in operating frequency and an improvement in IPC could result in the same net benefit.

    Take care,
    Anand
  • shompa - Friday, March 30, 2012 - link

    *hint* Use top on a iOS/Android device and you will see 30-60 processes at all time. The single threaded, single program thinking is Windows specific and have been solved on Unix since late 1960. Todays Windows phones are all single threaded because windows kernel is not good at Multit hreding.

    With many processes running, it will always be beneficial to have additional cores. Apple have also solved it in OSX by adding Grand central dispatch in their development tools making multithreaded programs easy.

    Iphoto for Ipad: Editing 3 million pixel will demand huge amount of CPU/GPU time + memory. Apple have so far been able to program elegant solutions around the limits of ARM CPUs by using NOVA SIMD extensions and GPU acceleration. An educated guess is that Iphoto is not fully optimized and will be at later time.

    (the integrated approach gives Apple a huge advantage over Android since Apple can accelerate stuff with SIMDs. Google does not control the hardware and can therefore not optimize its code. That is one of the reasons why single core A4 was almost as fast as dual core Tegras. I was surpassed when Google managed to implement their own acceleration in Andriod 4.X. Instead of SIMD, Google uses GL, since all devices have graphics cards. This is the best feuture in Android 4.x.)
  • name99 - Thursday, March 29, 2012 - link

    [/quote]
    Apple’s design lifespan directly correlates to the maturity of the product line as well as the competitiveness of the market the product is in.
    [/quote]

    I think this is completely the wrong way to look at it. Look across the entire Apple product line.
    I'd say a better analysis of chassis is that when a product first comes out, Apple can't be sure how it will be used and perceived, so there is some experimentation with different designs. But as time goes by, the design becomes more and more perfected (yes yes, if you hate Apple we know your feelings about the use of this word) and so there's no need to change until something substantial drives a large change.

    Look, for example, at the evolution of iMac from the Luxo Jr version to the white all-in-on-flatscreen, to the current aluminum-edged flatscreen which is largely unchanged for what, five or six years now. Likewise for the MacBook Pro.
    Look at the MacBook Air. The first two revs showed the same experimentation, trying different curves and angles, but Apple (and I'd say customers) seems to feel that the current wedge shape is optimal --- a definite improvement on the previous MBA models, and without anything that obviously needs to be improved. (Perhaps the sharp edges could be rounded a little, and if someone could work out the mechanicals, perhaps the screen could tilt further back.)

    And people accept and are comfortable with this --- in spite of "people buy Apple as a fashion statement idiocy". No-one will be at all upset if the Ivy League iMacs and MBAs and Mac Minis look like their predecessors (apart from minor changes like USB3 ports) --- in fact people expect it.

    So for iPhone and iPad. Might Apple keep using the same iPhone4 chassis for the next two years, with only minor changes? Why not? There's no obvious improvement it needs.
    (Except, maybe, a magnet on the side like iPad has, so you could slip a book-like case on it that covered the screen, and switched it on by opening the book.)
    Likewise for iPad.

    New must have features in phones/tablets (NFC? near-field charging? waterproof? built-in projector like Samsung Beam?) might change things. But absent those, really, the issue is not "Apple uses two year design cycles", it is "Apple perfects the design, then sticks with it".
  • mr_ripley - Thursday, March 29, 2012 - link

    "In situations where a game is available in both the iOS app store as well as NVIDIA's Tegra Zone, NVIDIA generally delivers a comparable gaming experience to what you get on the iPad... The iPad's GPU performance advantage just isn't evident in those cases..."

    Would you expect it to be if all the games you compare have not been optimized for the new ipad yet? They run at great frame rates but suffer in visuals or are only available at ipad 2 resolutions. The tegra zone games are clearly optimized for Tegra while their iOS counterparts are not optimized for the A5x, so of course the GPU advantage is not evident.

    This comparison does not seem fair unless there is a valid reason to believe that the tegra zone games cannot be further enhanced/optimized to take advantage of the new ipad hardware.

    I suspect that the tegra zone games optimized for A5x will offer a tangibly superior performance and experience. And the fact that the real world performance suffers today does not mean we will not see it shortly.
  • Steelbom - Thursday, March 29, 2012 - link

    Exactly this.

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