Apple A4

Discussion in 'iPad' started by Sushi Dude, May 2, 2010.

  1. Sushi Dude macrumors newbie

    Sushi Dude

    Nov 8, 2009
    On the apple website it says the A4 runs at 1GHz speed but it is so much more powerful than a 1GHz Chip. Why and how is this? And do you think, in the future, apple will make CPUs for there computers?
  2. celticpride678

    Feb 15, 2009
    Boston, MA
    It is so much more powerful than a 1GHz chip because iPhone OS does not require that much processor power, which is why it is so fast.

    I don't see Apple making their own notebook processors in the future.
  3. jlasoon macrumors 6502a

    Jun 1, 2006
    Orlando, FL
    It's mind boggling as to how responsive this iPad actually is. I absolutely love it. I haven't used my MacPro in 3 days:)
  4. Sushi Dude thread starter macrumors newbie

    Sushi Dude

    Nov 8, 2009
    I have not used my iMac 5 Days. In fact I am typing this on an iPad.
  5. Maaz macrumors 6502a

    Mar 13, 2010
    Yeah, honestly the ipad is very fast it's kinda scary.
  6. mymacrumorse macrumors member

    Jun 25, 2008
    I watch sports and stuff on my laptop but if I would like to browse or read something I save it for my iPad. It's so darn pretty:D
  7. shrimpdesign macrumors 6502a


    Dec 9, 2005
    Instead of using fast processors and memory to solve the problem of speed, Apple has chosen to rely more on expert software engineering. They optimize the hell out of the iPhone OS.

    This is why the Joojoo has much beefier specs than the iPad, but is much slower.
  8. Sushi Dude thread starter macrumors newbie

    Sushi Dude

    Nov 8, 2009
    The iPad has already uber killed the netbook and when mutitasking comes out it might even kill the laptop.
  9. vw195 macrumors 6502

    Dec 27, 2008
    Netbooks sold 34 million in 2009, They are expected to sell 40 million in 2010. Doesnt seem to be uber killed, merely somewhat bruised
  10. TuffLuffJimmy macrumors G3


    Apr 6, 2007
    Portland, OR
    Not all chips are created equal. For example, you can't compare a 1GHz A4 in an iPad with a 1GHz CoreDuo in a netbook. They're just different.
  11. AR15MBP macrumors regular

    Jan 6, 2009
    there's been a lot of speculation on the chip. is it for sure an offshoot of the ARM Cortex A8? and is it single core for sure?
  12. Fonzmeister macrumors member

    Apr 25, 2010
    Portugal - Lisbon
    People can't compare a mobile device CPU with the CPU's used on computers.

    Totally different technologies (CISC vs RISC design), different objectives, different power requirements.

    A 1GHz RISC CPU (such as the A4) can be faster than a intel core2duo at 2GHz, if the software is designed to take advantage of the RISC design.
    Sure, this is only true on very specific tasks.
  13. Stealthipad macrumors 68040


    Apr 30, 2010
    If Apple would only give me folders and the ability to store files on my iPad. I like it too but hope to keep my files on my iPad.

    Then lets get a good MS Office program.:eek:
  14. wombat888 macrumors 6502a

    May 10, 2008
    For anyone who doesn't know what GHz (or MHz, or KHz or just Hz) means, it refers to how many times the chip cycles per second.

    Think of it as a car engine's RPM (revolutions per minute). The more RPM an engine is capable of, the greater its max power, all else being equal.

    That's the catch, though ... a 2.0L engine needs to run through two cycles to produce the power a 4.0L engine makes in one cycle (VERY ballpark). In other words, the number of cycles per second for a chip, or the number of revolutions per minute for an engine, is half of the equation. The other half is how much it can do per cycle/revolution.

    A 4.0L engine converts, literally, four liters of fuel/air mixture to energy per revolution, while a 2.0L engine converts two liters per revolution. That's why a smaller engine needs to run faster.

    A chip that can process more data per cycle similarly needs fewer Hz to achieve the same thing.

    With the A4, as far as I know, we only know half of the equation. My Nexus One has a 1GHz snapdragon processor, but I'm confident the A4 is a lot more powerful, because of the other half of the equation ... ie the snapdragon is like a 2.0L and the A4 is like a 4.0L (numbers super-inexact for illustration only).
  15. blackNBUK macrumors 6502a

    Feb 19, 2010
    Definitely true; I'd wager that on pure processing power a 1GHz CoreDuo would be faster than an A4 chip. In exchange it would also suck down a whole load more power.

    I think that the reason that the iPad feels so fast is a combination of factors that include good mobile class hardware. Using that hardware in the best way is also a factor; for example I would expect a decent amount of the speed comes from using the graphics processor to deal with as much as possible. Finally, and most importantly, I think that they have focused on responsiveness instead of pure speed. When I use my iPod Touch, virtually all of the time the UI responds immediately which gives the impression of speed. However to achieve this they have had to make compromises; for example in Safari scrolling and zooming work amazingly smoothly and responsively but quite often the page is either checker-boarded or blurred. They could have tried to render the page exactly all of the time but then they would have had to sacrifice the natural responsiveness.
  16. PoisonScorpion macrumors member

    Oct 6, 2009
    Wombat has a simplified example but is a good example.

    For more details take a look at the Megahertz myth. Some processors are more efficient than others.

    Take a runner and two mazes, one simple and one complex. The simple one is more efficient than the complex one therefore can be completed faster even though the runner (hertz speed) is the same. The simple maze is more "efficient" vs the complex one.

    Some processors are better than others for some things.
  17. ct2k7 macrumors 603


    Aug 29, 2008
    London or Florida
  18. blackNBUK macrumors 6502a

    Feb 19, 2010
    Wombat's metaphor is pretty good but I think we should be clear where the A4 is in relation to desktop chips. The engine of an Intel Core2Duo (for example) is both larger and revs higher.

    The big advantage of the ARM architecture in the A4 chip is power consumption. Obviously by using less power you can get longer battery life. Alternatively you can get the same battery life with a smaller battery which saves weight. Low power consumption also means that you have to deal with less heat which means that you don't need fans which again saves weight. It's a bit like reducing the weight of a car; making the CPU more power efficient improves everything in a mobile device.
  19. MikhailT macrumors 601

    Nov 12, 2007
    The CPU (other related as well) industry have stopped caring about the MHz/GHz a short while ago (like 5 years ago). Which is a good thing because we need to focus on everything else, the efficiency per clock, the power consumption and etc. Not to mention we have moved toward adding more cores per chip.

    The today 1GHz A4 chip is much more efficient compared to the 1GHz chips 4-5 years ago. Imagine that at a time, 1GHz were consuming 50-100 TDP (watt of heat required to dissipate by the cooling system), with A4 chip, it can be lower than 10 TDP and still offer the same performance or more at same speed.

    In another (bad but it works) example, imagine a 12x12 room filled up by a single computer and its clock speed is at 1GHz and now imagine that room being shrunken down into the size of the iPhone without losing any performance or increasing performance. Imagine the amount of heat being thrown out by that room-sized CPU and now imagine what kind of heat for the iPhone sized.

    Now modern chips do more per clock than they did years ago. What does that mean? Let's imagine a ten blocks street, point A to B on each side on this street. The old 1GHz chip was only able to take one lane of car on this street, meaning only one car per second(or clock) were able to get to A to B.
    Today's 1GHz chip is more of a highway, it has 4-8 lanes of each. That means it can process 4-8 cars per clock, but there are other extra features. There are instruction sets that allow the chip to process bus/doubledecker buses at once instead of taking up 2-4 cars worth of seconds. So if there's a bus coming, the old 1Ghz will have to do 2-4 worth of clock to let them in, the modern chip can do it in one clock.

    Those examples are not very accurate but they do explain the concepts.

    As for Apple producing the chips for desktops, not going to happen. The reason is that its far cheaper to buy the standard x86 chips which are far more powerful and much more faster than the actual ARM (a4) chips per clock and not to mention multiple cores also. While x86 chips throw out far much greater heat (we're talking 60-130 TDP), the desktops have more area for the heat to dissipate, so it's okay to use the chips there. It's not worth the low performance per clock for desktops/laptops. It only makes sense in mobile devices like iPad/iPhone.
  20. GoHack macrumors member

    May 7, 2009
    Palmdale, CA
    Anyone here know if the A4 is a dual core CPU? It would need to be, in order to support Apple's next OS, wouldn't it?

    It has a built in GPU, and memory controller.

  21. MikhailT macrumors 601

    Nov 12, 2007

    The iPhoneOS 4.0 doesn't require a dual core CPU, it'll run on 3G/3GS iPhone after all. It'll scale up to the number of cores whenever the devices with such chips come out. According to some devs, iPhoneOS 4.0 has GCD implementation in it.

    A4 is a design based off ARM's Cortex A8, which is a single core. The Cortex A9 is the one with dual/quad core designs but that's a year or two away.
  22. wombat888 macrumors 6502a

    May 10, 2008
    I doubt the A4 is dual core, and I doubt that will be a requirement for any version of the iPhone OS on the horizon. I could be wrong about either or both statements.
  23. lilo777 macrumors 603

    Nov 25, 2009
    A4 performs just as a contemporary 1Ghz chip is expected to perform. Faster than 600MHz mobile chips, marginally faster than some 1GHz mobile chips (like snapdragon, more details here) and slower than the slowest Intel chips (See CNET performance tests here. In some tests A4 is 6x slower than Atom). As someone already mentioned, the perception is somewhat deceiving. iPad does feel fast but that's not because of the processing power. It feels fast because apps (like Safari) are optimized to act fast (by scrolling unloaded pages etc.). But if you try to run something that requires real processing power (like Flash ;)), A4 will choke.
  24. jaw04005 macrumors 601


    Aug 19, 2003
  25. MikhailT macrumors 601

    Nov 12, 2007
    Not that I disagree with you, but using one of the links to back up what you're saying is wrong, the CNet's "performance test" against Atom link. That's not even a benchmark at all. Comparing an Atom 1.6GHz, 1GB against an ARM A8 design at 1GHz, 256MB with no information on the netbook like which browser were used for the site rendering or javascript tests? It doesn't even explain the battery life for both, which again as mentioned a few time, ARM beats Atom for battery life due to the lower power consumption.

    The real question is how does Atom at 1GHz compare to the A8 at 1GHz. It'll equal or be a bit faster than A8's performance for sure but at what cost to the battery life?

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