Apple A7 is now 64-bit

[Eug]

Does the iPhone 5S even have 2 GB RAM? I'm wondering if it still might only have 1 GB. I hope not, for future proofing reasons.

To put it another way, due to RAM overhead, must a 64-bit phone require 2 GB, if the 32-bit little brothers (iPhone 5 and likely 5C) have only 1 GB? By the sounds of the discussion here, it seems like 2 GB might be recommended for a 64-bit iOS, even if 32-bit iOS 7 runs perfectly well on the previous 1 GB flagship iPhone 5.

BTW, for reference, the A6 is 95 mm2, so the A7 is only a 7% increase in physical size, but the A6 was on a 32 nm process.

 

[Rakehellion]

Does the 5S even have 2 GB RAM? I'm wondering if it still might only have 1 GB. I hope not, for future proofing reasons.

BTW, for reference, the A6 is 95 mm2, so the A7 is only a 7% increase in physical size, but on a 32 nm process apparently.

Why would 2GB be a necessity?

And high end-phones aren't designed to be future-proof. You ditch them in 2 to 3 years, tops.

 

[soccerballtux]

They've doubled the speed every year and haven't gone over two cores yet, I don't see why.

because cortex-A57 is a tweaked cortex-A15 with 64b.
edit: long time ago I must have misread this article, which says 20-30% faster: http://www.anandtech.com/show/6420/arms-cortex-a57-and-cortex-a53-the-first-64bit-armv8-cpu-cores

Or they're on their way to ditching Intel entirely. Apple has an ARM architectural license so they could conceivably design their own high performance ARM chip and put them in MacBooks.

+1 that's the endgame IMHO

The reason why the A7 is 64-bit is to prepare for when a 64-bit SoC will actually be needed by Apple. By the time the iPhones and iPads of the future are ready for 4GB+ of RAM, most major apps on the App Store will be optimized for a 64-bit SoC. This will give Apple a major advantage over the competition because Apple will have substantially more apps that are a "generation" ahead of the competition. This is assuming that "the competition" does not develop 64-bit SoCs before phones with 4GB+ of RAM becomes relevant.

I don't see it.
Only way this makes sense is for experience with 64b ARM design and coding, so they can port OSX.

 

[Eug]

Why would 2GB be a necessity?

And high end-phones aren't designed to be future-proof. You ditch them in 2 to 3 years, tops.

I would say the two biggest factors of importance for OS updates are:

1) RAM size.
2) CPU speed.

If the iPhone 5S has 2 GB RAM, along with its 64-bitness, I suspect it will last at least one iOS generation longer than the iPhone 5. My wife will still be using our iPad 2 (512 MB RAM, A5) and her iPhone 4 (512 MB RAM, A4) with iOS 7. The iPad 2 came out in 2011, and the iPhone 4 came out in 2010.

The iPhone 4 has been able to last this long for iOS updates probably because it has 512 MB RAM, twice that of the iPhone 3 GS, and 4 times that of the iPhone 3G.

---

BTW, just a reminder:

http://www.extremetech.com/computin...-rare-hand-made-custom-cpu-and-a-tri-core-gpu

A6 was hand laid out. I wouldn't be surprised to hear it's the same for A7.

 

[Exophase]

because cortex-A57 is a tweaked cortex-A15 with 64b.
edit: long time ago I must have misread this article, which says 20-30% faster: http://www.anandtech.com/show/6420/arms-cortex-a57-and-cortex-a53-the-first-64bit-armv8-cpu-cores

Apple A6 isn't using Cortex-A15 and Apple A7 isn't using Cortex-A57. They're using an in-house CPU design.

 

[Vesku]

How would that make them any money?

Companies that want HPC 64 bit ARM systems exchanging money for said systems? Calxeda and AMD as well as a lot of analysts think demand exists for such hardware.

 

[Railgun]

Why is everyone fixated on memory as the only advantage to 64 bit? It alone is not the end all be all advantage. Being the cpu section, I would have thought most of you would get that.

 

[MisterMac]

In a process tech world - do people or apple themselves really think they can go against Intels mainstream desktop\laptop lines?

Even in a timeframe of 5 to 10 years?


Apple's resurgence came from the power x86 brought them - by taking that away for "good enough" computing with ARM won't they kill of all the hipsters that loved them in the first place for the power and the outside shiny design?

 

[ShintaiDK]

In a process tech world - do people or apple themselves really think they can go against Intels mainstream desktop\laptop lines?

Even in a timeframe of 5 to 10 years?


Apple's resurgence came from the power x86 brought them - by taking that away for "good enough" computing with ARM won't they kill of all the hipsters that loved them in the first place for the power and the outside shiny design?

Apple will change as previous when there is something better. I wouldnt be surprised if this was their last SoC, or only will be one more.

 

[Dribble]

A 64-bit app isn't going to need twice as much storage - by storage I assume you mean where your apps go, like flash. There's no reason why it should need any more storage at all, except that the instructions are less dense than the Thumb-2 ones currently available in 32-bit ARM (I have no idea if this is something iOS apps use or not. Android ones generally do). But that has nothing to do with it being 64-bit.

Yes it will. A 64 bit app needs to use 64 bit pointers which are twice the size of 32 bit pointers. Depends on the programme but you are looking at say 25% more memory needed to run exactly the same programme compiled for 64 bit not 32 bit.

Not that it really matters as no one will write 64 bit phone apps as there's no need and they'd only work on the 5S, they'll all be 32 bit for years to come yet - in the PC would we are still switching despite 64 bit arriving about 10 years ago. 64 bit will be pretty well completely unnecessary in this phone, it's there because Apple are looking to unify their cpu architecture and laptops will need 64 bit.

 

[StrangerGuy]

Why is everyone fixated on memory as the only advantage to 64 bit? It alone is not the end all be all advantage. Being the cpu section, I would have thought most of you would get that.

Because dissing Apple is cool bro.

 

[TerryMathews]

Because dissing Apple is cool bro.

Only to a true believer is questioning why a device with 2GB of RAM needs 64 bit addressing "dissing Apple".

 

[tommo123]

if they want to move to x64 then they can't do it all in one go can they?
2-3 years from now will be an ios update that's only for x64 iphones as they'll have enough out by then.

it's like when AMD moved to 64 bit. no difference really bar a handful of apps that were 64bit. took a while to gain traction. same here

 

[StrangerGuy]

Only to a true believer is questioning why a device with 2GB of RAM needs 64 bit addressing "dissing Apple".

Please tell me does that hurt anything for just being there? Are kittens slaughtered every minute because of 64-bit? Apple haters just gonna hate.

 

[TerryMathews]

if they want to move to x64 then they can't do it all in one go can they?
2-3 years from now will be an ios update that's only for x64 iphones as they'll have enough out by then.

it's like when AMD moved to 64 bit. no difference really bar a handful of apps that were 64bit. took a while to gain traction. same here

The difference there was some devices were bumping into the address space limit.

Since Apple just announced their new iPhone and didn't trumpet "Now with 4GB of RAM twice as much as Android!" I'm going to assume they didn't load the device up with that much RAM.

Also, Apple's walled garden is vastly different than the PC marketplace. If Apple wants to enforce 64-bit safe apps only no one is stopping them. It isn't like Windows where you're fighting developers writing programs without following your guidelines for years.

 

[TerryMathews]

Please tell me does that hurt anything for just being there? Are kittens slaughtered every minute because of 64-bit? Apple haters just gonna hate.

This is a tech forum. Excuse us if we discuss technical merits of running 64bit on a device with a 2GB memory map.

"Haters gonna hate" is your own reducto ad absurdum because someone dared question Apple.

Get over it. I'd be saying the same thing if Samsung were doing it.

My question to you, is does it help anything at this time being there? Or is it just a waste of transistors at this point.

Someone else made the point that Apple needed 64 bit devices out to people now so that there would be enough out there when they obsoleted the 32 bit OS.

Why? Why can't Apple maintain concurrent 32 bit and 64 bit code bases? Unless they've fired all the program managers from the early 2000s, they should have plenty of people experienced with that as they used to maintain concurrent PPC and X86 bases in OS X.

32 bit on small devices and 64 bit on large devices would maximize performance, since as we all know pointer and address sizes double on a 64 bit OS. That is not a trivial amount of space.

 

[Nothingness]

Apple's resurgence came from the power x86 brought them - by taking that away for "good enough" computing with ARM won't they kill of all the hipsters that loved them in the first place for the power and the outside shiny design?

Apple's success came from their iDevices, all of which are ARM. In case you didn't pay attention more than 3/4 of Apple revenues come from ARM based devices. They are vertically integrated from CPU up to end user device.

That's why they won't switch away from ARM for some years, if ever.

 

[tempestglen]

In a process tech world - do people or apple themselves really think they can go against Intels mainstream desktop\laptop lines?

Even in a timeframe of 5 to 10 years?


Apple's resurgence came from the power x86 brought them - by taking that away for "good enough" computing with ARM won't they kill of all the hipsters that loved them in the first place for the power and the outside shiny design?

x86 product- Mac only accounts for less than 15% revenue, I think.

In 2007, apple jumped to x86 and arm simultaneously, Apple's resurgence came mostly from arm devices(iPod,iphone,iPad etc) not from x86 chips.

Furthermore, the Britain ARM Holding co. was founded by apple and Acorn in 1990， arm chipset was for the famous first PDA "Newton" from apple. Apple is the "father" of ARM, but apple sold out ARM shares in1996 for saving apple itself.

DEC's P.A. center in 1990s designed the best arm micro architecture-- Strong ARM(later as intel's xscale) and apple cooperated with P.A.(DEC) tightly. In 2006, the P.A.'s pwrefficency chipset was chosen as Mac's heart, but 2007 apple turned to intel leaving P.A. in angry, and 2008 apple merged P.A..Steven Jobs gave P.A. a very radical design target, the fruit is Swift A6 in iphone5 and today's 64bit A7.

I believe that ARM and P.A. are completely involved in apple's history, not surprised if apple drops x86 for its customized ARM micro architecture.

Therefore, the story of ARM vs X86 will between former DEC(P.A.) and Intel, the "StrongARM "vs "Xscale"?

StrongARM MKII is coming! Watch out for it, intel!

 

[StrangerGuy]

Apple's success came from their iDevices, all of which are ARM. In case you didn't pay attention more than 3/4 of Apple revenues come from ARM based devices. They are vertically integrated from CPU up to end user device.

That's why they won't switch away from ARM for some years, if ever.

Screw this concept called "business strategy". Getting Intel as the sole CPU supplier from top-to-bottom is clearly a great idea, just look at those PC OEMs are doing oh-so-well at the moment.

 

[tempestglen]

Screw this concept called "business strategy". Getting Intel as the sole CPU supplier from top-to-bottom is clearly a great idea, just look at those PC OEMs are doing oh-so-well at the moment.

With regard to the relationship between intel and OEMs, the first phrase appears in my head is "Sex Slave".

 

[ShintaiDK]

Screw this concept called "business strategy". Getting Intel as the sole CPU supplier from top-to-bottom is clearly a great idea, just look at those PC OEMs are doing oh-so-well at the moment.

Try check other segments. TVs, cams etc are all in a disasterous negative spin. But it seems people can only see tablets and smartphones as how the market is.

 

[Exophase]

Yes it will. A 64 bit app needs to use 64 bit pointers which are twice the size of 32 bit pointers. Depends on the programme but you are looking at say 25% more memory needed to run exactly the same programme compiled for 64 bit not 32 bit.

Did you read my entire post or did you stop at the part you quoted? I talked about the extra RAM requirements needed by pointers already.

When someone says storage they usually mean the permanent kind, not RAM. In this particular context it's especially obvious that that's what he means since he said that it'll be your carriers who benefit, ie from increased traffic due to larger app downloads. And I specifically explained that this is the type of storage I was talking about. This doesn't have anything to do with how much RAM is used. Apps don't contain pointers in their files.

 

[ultimatebob]

Yeah... it just seems really weird to put a 64 bit processor in a phone that only has 2 GB of memory with no way to add memory.

Maybe they are just getting the developers ready for 64 bit... I don't know.

 

[StrangerGuy]

With regard to the relationship between intel and OEMs, the first phrase appears in my head is "Sex Slave".

Yeah when Intel declined the iPhone SoC business and Apple took up ARM Apple probably have no idea then how big a bullet they have dodged. Easily the best decision they made in recent years.

 

[knutinh]

Ok so 64 bits allows you to address >4GB of memory efficiently and when including memory-mapped devices, that threshold sits at somewhere below 4 GB. I still don't get why Apple would want/need to introduce potentially redundant transistors in todays products in order to "be ready" or "force developers in the right directions". Having the power of vertical integration that Apple has, they could simply force all AppStore apps to be compiled for 32/64 bits, and introduce 64-bit hw whenever it was really needed?

Many number-crunching tasks tends to be vectorized (SIMD, Neon) at a width (64,128,256) that is not equal to the "number of bits" of the cpu. Often the data-types will be smaller (int8, float32). So what do programs do with the "scalar" 64-bit capability unless they are working on ... 64bit integers? I can see why some operations on arrays of int8/16/32 might be faster by treating them as multiple int64s, but then why not use the SIMD engine?

My assumption is that there is some cost to be paid. More transistors for a 64-bit adder/multiplier at a given clock. More instruction cache for 64-bit adresses.

-k