Apple Announces A7, World's First 64-bit Smartphone SoC

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• mavere - Tuesday, September 10, 2013 - link

  I think you're going to be repeating that line over and over for the next few weeks, as the commentariats dump their drivel.

• lilo777 - Tuesday, September 10, 2013 - link

  "64Bit isn't just for more addressable RAM."
  
  What else is it for? I understand that calculations are still done in 32-bits (even x86 processors do that, only Itanium/IA64 class processors have 64bit datapath).

• danbob999 - Tuesday, September 10, 2013 - link

  x86-64 also have a 64 bit datapath.
  
  64 bit is mostly useful for some scientific applications. 99% of iOS apps out there would be fine with 16 bit (as long as they could address all the RAM)

• danbob999 - Tuesday, September 10, 2013 - link

  and the other 1% is fine with 32 bit

• ninjaquick - Tuesday, September 10, 2013 - link

  It isn't a datapath thing. Currently, any precision math, or long hash work/encryption (common for apps using data) require 2 or 4 clocks to handle, which means higher consumption and lower performance. 64 bit registers means that drops to a theoretical 1/2 of power and clocks used to process. Which is a massive increase in throughput. Yes, most apps do not take advantage of this, but they will if they are apps that tend to eat CPU time.

• ninjaquick - Tuesday, September 10, 2013 - link

  64 means you can use 64 bit registers and arguments for instructions, typically per clock, so code that uses 64 arguments can be run faster, rather than spliting high precision / length instructions into two steps. This is especially good for reducing time spend on memory transactions, which means low power ram can be used, retaining high efficiency with improved performance. Plus this allows for virtualization (ARMs implementation) which can in turn mean sandboxing apps. Most apps may be natively written with 16 / 32 in mind, but using 64 does not necessarily mean they need to use loads of ram, using 16 megs of ram, with 64 bit registers can still yield performance boosts. This is essentially *doubling* the available resources / performance of the pipeline.

• danbob999 - Tuesday, September 10, 2013 - link

  64 bit doesn't double de performance.
  Let say you add 1 + 1. It will be just as fast on 8, 16, 32 or 64 bits.
  If you need integers (not floating point) numbers higher than 4 billion, then 64 bit is faster. If you only use these numbers in 0.01% of you calculation, then you get a speed boost 0.01% of the time.
  They doubled the number of registers, which will improve performance (less transfers to RAM), but has nothing to do with 64 bit.

• easp - Tuesday, September 10, 2013 - link

  You do know that people use computers as something more than glorified calculators, right? Not all computing is "numeric," it involves other data types, like strings, and other operations, like logical comparisons.

• danbob999 - Tuesday, September 10, 2013 - link

  Logical comparisons aren't faster on 64 bit. Only you can compare larger numbers at the same time. Branching isn't faster on 64 bit.
  Strings do not really benefit from 64 bit either. They are array of bytes. Where is the benefit of 64 bit?

• StevenRN - Tuesday, September 10, 2013 - link

  My 32 BIT CRC run almost 2X faster when converted to 64 BIT. String copies and encryption run almost 2X faster (with no code changes) run almost 2X faster. Long word optimized string searches can also run faster in many cases by not doing simply "byte" wise operations.