iPhone Why Go 64bit?

Discussion in 'iOS 7' started by sparcusa, Feb 20, 2014.

  1. sparcusa macrumors newbie

    Feb 20, 2014
    I'm curious as to why apple would change the 5S over to a completely 64bit architecture and then only include 1 gig of RAM. Why would they do that? Is there any performance benefit? Thoughts?
  2. Curun macrumors 6502


    Sep 10, 2013
    Because 1GB of RAM is sufficient.
    They wanted to.

    Classic example of what came first, Chicken or the egg. Software won't be developed and deployed until hardware exists in mainstream, hardware isn't going to be developed for software that doesn't exist. Apple made a leap to lay the foundation of what is to come.

    Look at Bluetooth 4.0LE. Apple integrated it in 2011 in the iPhone 4S. There wasn't much purpose, but they laid the foundation in hardware. Now, 2014, bluetooth beacons utilizing that 4.0LE hardware is being deployed in stores, sporting events, cars, luggage tags, that all work backwards 3 generations of devices.
  3. cmChimera macrumors 68040


    Feb 12, 2010
    What was said in the first reply is true too, but there is a performance boost as well. It's a myth that the only benefit to 64bit is to have more than 4 gigs of RAM.
  4. Charliebird macrumors 6502a

    Mar 10, 2010
    I think it's because Apple has bigger plans for the A chip line. Maybe future laptop and desktop implementations.
  5. MisakixMikasa macrumors 6502a


    Aug 21, 2013
    Waterloo, Ontario, Canada
    Still to hard for ARM chip emulating current x86 applications. Unless you want some short of Windows RT thing on Mac...
  6. dlewis23 macrumors 6502a

    Oct 23, 2007
    That's why Apple is not going to put ARM in a notebook.
  7. Charliebird macrumors 6502a

    Mar 10, 2010
    I see it has a long term play. Apple can fab an A7 chip for $20 bucks. I'm sure they're paying Intel over $100 per processor. Plus Apple is first and foremost an engineering company and they now have the in-house expertise to engineer their own arm based processors. Why else create an 64-Bit processor where the benefits for mobile devices are minimal but would have huge potential for laptop\desktops. I'm not saying the changeover is coming anytime soon but Apple took a big step to go that direction by going 64 bit.

    Not long ago people said Apple would never switch over from PowerPC chips.
  8. dlewis23 macrumors 6502a

    Oct 23, 2007
    The benefits for a laptop/desktop doesn't matter because there are already 64bit processors for laptops/desktops that are incredibly fast and are very efficient and only going to get more efficient.

    The benefit of a 64Bit processor in a mobile device like an iPad comes in with real world pro applications. Imagine a real version of Photoshop on your iPad. 64Bit ARM is just the first step in many but not one that ends in a ARM based mac because they will end up with the same problem MS has with Windows RT.
  9. Altis macrumors 68030

    Sep 10, 2013
    Why go 64-bit?

    Because people will think it's better. It's mostly a marketing thing as of current.

    Everyone making all kinds of claims about how and why it's better, in what apps it's useful, etc. and people who don't know anything about it see it as a reason to upgrade, new feature...

    It was destined to happen at some point. They just did it to capitalize on those points, and get the transition over with.

    My $0.02 anyways ;)
  10. GoSh4rks macrumors 6502

    Sep 14, 2012
    ARM is far too slow to replace x86 in any current Mac. It would have to be a new product.
  11. C DM macrumors Westmere

    Oct 17, 2011
  12. Charliebird macrumors 6502a

    Mar 10, 2010
    Yes, there's currently a large performance gap between Apple's Arm chips and Intel Core processors. However that gap is closing and Apple's Arm chips have a power savings advantage and big price advantage. Apple has never been afraid to implement disruptive technology. Even if Apple never makes the transition to their own Arm chips it could be used as leverage with Intel for better pricing. Intel's competition with AMD is pretty much over so their isn't much to keep Intel's pricing inline right now.
  13. eclipse01, Feb 21, 2014
    Last edited: Feb 21, 2014

    eclipse01 macrumors 68020


    May 16, 2011
    Eau Claire, WI
    Apple is super stingy on their RAM for some reason, they say they don't need it as bad as people think but that is complete BS in my mind.

    this is why anything below 4S force closes all the time and the Ipad 1 which is only a few years old is basically a paperweight now...
  14. cynics macrumors G4

    Jan 8, 2012

    Using a legacy device w/ 512mb of RAM on iOS 7 is a real bare IMO.

    If I'm running Pandora every app wants to reload way too often.

    With the 4S people said, 512 mb RAM is more then enough blah blah blah. Now here we are and with apples own update to iOS 7 it turns out it's not enough.

    The same thing will happen to the 5, 5S, rMini, Air etc etc...
  15. BugsysDad macrumors newbie

    Feb 26, 2014
    Danvers, MA
    Running a 64 Bit OS will let you run 64 bit programs AND utilize more than 4GB of RAM, if you have more that 4GB installed.

    You don't really get a performance boost otherwise - the performance boost comes from the increased availability of memory made possible by using the 64 Bit OS.
  16. jonasdamn macrumors 6502a

    Mar 4, 2013
    Ability to use 4GB RAM and more is not the only one of the 64 bits advantages...
  17. Mr. Retrofire macrumors 601

    Mr. Retrofire

    Mar 2, 2010
    Both things are wrong.

    The 32-Bit OS X kernel and therefore the iOS 32-Bit kernel supports > 4 GB RAM and 64-Bit applications.
  18. BugsysDad, Feb 27, 2014
    Last edited: Feb 27, 2014

    BugsysDad macrumors newbie

    Feb 26, 2014
    Danvers, MA
    OK then would you mind enlightening me with some of these other benefits of having a 64 Bit OS?


    I wasn't aware Apple differed from PCs in this area - I stand corrected.
  19. Xenomorph macrumors 65816


    Aug 6, 2008
    St. Louis
    From Wikipedia:
    "Some 64-bit programs, such as encoders, decoders and encryption software, can benefit greatly from 64-bit registers..."

    From Microsoft:
    "A 64-bit architecture provides more and wider general-purpose registers, which contribute to greater overall application speed. When there are more registers, there is less need to write persistent data to memory and then have to read it back just a few instructions later. Function calls are also faster in a 64-bit environment because as many as four arguments at a time can be passed in registers to a function."

    When Apple had their big event that showed off the iPhone 5S, they talked about the A7 in detail, and even pointed out the registers (both general-purpose and floating-point).

    Basically, even with 1GB of RAM (or less), 64-bit software can do more in the same number of CPU cycles, and therefor run *faster* than the equivalent 32-bit program doing the same thing.

    People seem too focused on how much RAM a 64-bit CPU can address: that is probably Microsoft's fault, due to the limited way they set up Windows (32-bit Linux had no problem with >4GB of RAM). You don't need 4GB+ of RAM to take advantage of 64-bit. That wasn't the focus of the A7 or iPhone 5S. Changing the architecture now and laying the foundation for later technology was.
  20. jonasdamn, Feb 27, 2014
    Last edited: Feb 27, 2014

    jonasdamn macrumors 6502a

    Mar 4, 2013
    As i know/ heard that:
    1.)It has more register which can handle large memory areas simultaneously.
    2.)Higher bandwidth from more channels.
    3.)Performance gain on applications which handle large data arrays.
    4.)64-bit ABI allows the generation of better code than the 32-bit ABI (by passing parameters on registers instead of on the stack, for instance).
  21. Menneisyys2 macrumors 603

    Jun 7, 2011
    To force you to upgrade to this year's models, which surely will have 2+GB of RAM.


    Lolz... You can't be serious.

    Yes, it IS sufficient - if you don't want to have more than one tab in Safari open.

    Again: lol.
  22. MattInOz macrumors 68030


    Jan 19, 2006
    As NAND gets faster I wonder if Apple are getting ready to delete the file system on iOS whole sale and have the whole of the Storage addressable by the processor.
  23. C DM macrumors Westmere

    Oct 17, 2011
    Why would 64-bit be needed for 2 GB of RAM?
  24. Menneisyys2 macrumors 603

    Jun 7, 2011
    You meant the other way around? ;) All 2/3GB Android devices are 32-bit only.

    Generally: look at the Safari / UIWebView memory usage on the 64-bit devices. It was very memory-hungry on 32-bit ones; on 64 bits, it's even worse.
  25. GreyOS macrumors 68040


    Apr 12, 2012
    Anyone considered/know more if moving to 64 bit could be partly due to codebase maintenance advantages? iOS and OS X probably share some base libraries and whatnot, as may be demonstrated by the recent SSL bug.

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