苹果新iPhone 64位处理器不实用？

苹果公司最新发表的 iPhone 5S即将上市。苹果为这款新版iPhone 手机采用了64位元的处理器架构，使其成为首款64位元的智能手机。但问题是，智能手机搭载64位元的存储器定址能力究竟能带来多大的性能进展？我怀疑这个问题的答案可能是：差别不大。 当ARM发布其V8架构，跨入64位元核心领域，最大的好处就是扩展了存储器定址范围，特别是针对服务器应用来说，其软件堆迭几乎完全都是基于64位元的定址存储器空间。 ARM与其十多家SoC合作伙伴正为该架构应用推动一项新计划，预计在2014年就能看到最初的成果。不过，截至目前为止，英特尔在低功耗服务器领域仍占据主导地位。 至于移动设备方面呢？目前似乎还没有针对64位元开发的软件。以当今32位元的主流系统来看，我们甚至离4GB主存储器的限制还有一段距离。因此，目前在移动设备上导入64位元的迫切性其实并不大。 根据The Linley Group公司分析师Kevin Krewell以及Real World Tech公司分析师David Kanter表示，他们并不看好iPhone 5S中采用64位元A7处理器能为用户带来什么价值。它纯粹就是抢先为未来的生态系统揭开序幕罢了。不过，Kanter指出，移动设备采用Gb级以上的主存储器，能够在简化虚拟存储器作业方面带来一些性能方面的优势。 我的意思并不是说智能手机永远不需要4GB以上的存储器。更贴切的问法应该是：用这么大的存储器能带来什么进展？ 苹果在为其新款M7传感控制器的传感器融合API开启一扇门时，也应该试着解决这个问题。三星先前为其最新款的Galaxy S采用了英特尔的芯片以及具备各种附加功能的传感器。而今，苹果也必须为其 iPhone认真思考能提供什么样的差异化与先进性能。 我从几年前开始就不再戴手表了，对于新兴的医疗保健与健身设备也没什么兴趣。但我知道，有一天还是会出现一些有趣的小玩意儿。 只是我怀疑没有人真的知道该怎么做──智能手机搭载64位元ROM与生物识别技术，这是多么吸引人的架构啊！是苹果公司如今正为此开启了一扇门，也掌握到了眼前的绝佳机会。但就像iPhone制造商一样，我也很好奇苹果究竟打算怎么做？ 本文授权编译自EE Times，版权所有，谢绝转载 编译：Susan Hong 参考原文：Apple Begs the 64-Bit Question，by Rick Merritt, SiliconValley Bureau Chief

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{pagination} Apple's iPhone 5S, arriving within days, begs the question of what can you do with 64-bit memory addressability in a smartphone. I suspect the answer is, "Not much." When ARM announced its V8 architecture for a 64-bit core the handwriting was on the wall. This was all about servers where the software stack is pretty much entirely based on 64-bit address spaces. ARM and as many as a dozen of its SoC partners are gearing up an interesting initiative here that will bear its first fruits in 2014. So far, Intel still has the lead in low-power servers. But mobile? There is no 64-bit software here yet. We are not approaching the 4 Gbyte main memory limit of today's 32-bit systems. Analysts I talked to, such as Kevin Krewell of The Linley Group and David Kanter of Real World Tech, said they don't expect to see any user value in a 64-bit A7 chip in the iPhone 5S. This is all about plowing the field for a future ecosystem. However Kanter noted there could be some performance advantages for simplifying virtual memory operations in devices at or above a Gbyte of main memory. Far be it from me to be the Luddite who says smartphones will never need more than 4 GBytes of memory. A better question is: What could they do with that much memory? Apple took a stab at that question when it also opened the door to a sensor fusion API riding on top of its new M7 sensor controller. Samsung had a jump on Intel with all the sensor bells and whistles in its latest Galaxy S phones. Now, Apple is calling the iPhone faithful to think different about what it could deliver. I stopped wearing watches years ago and have no interest in the new health and fitness devices popping up. But I don't doubt something interesting could emerge there someday. I suspect no one really knows what to do -- that's compelling -- with a smartphone that sports 64-bit memory spaces and biometrics, including Apple. The Cupertino company is just opening a door and seeing what passes through it. Like the iPhone maker, I'm curious to hear your thoughts, too.

相关阅读：
• 高通：走自己的路，让别家拼核去吧
• 苹果Touch ID是昙花，还是转折点？
• [图文报道]苹果发布iPhone 5S及5C，中国入首发名单wrXesmc