Why The New iPhone Will Not Use An A5X SoC
Rumors about 6th generation iPhone have reached a fever pitch. We've even got a rumored announcement date of September 12th. Amongst the many claims and speculations about the new iPhone, one in particular has stuck out to me. That claim is that the new iPhone will feature an A5X SoC (System on a Chip.)
The logic behind those who perpetrate this rumor is this: The first generation iPad shipped with an A4 processor. A few months later, the iPhone 4 shipped with an A4 processor. In 2011, the iPad 2 shipped with an A5 processor. Later that year, the iPhone 4s shipped with an A5 processor. This year, Apple shipped the third generation iPad with an A5X processor. So, logically, this year's iPhone will ship with an A5X processor, right? Wrong, and here's why.
The reason why Apple (or any other company for that matter) upgrades the processors in their devices is to improve performance where performance is lacking. The two most important parts of an SoC are the CPU (Central Processing Unit) and the GPU (Graphics Processing Unit).
The CPU is upgraded to improve performance for tasks like; opening and switching apps, processing files (example: exporting a 1080p video in iMovie), rendering webpages, ect.
The GPU is upgraded to; smooth out graphical transitions, increase frame rates, handle anything that involves the display.
Apple introduced the A5X in the 3rd generation iPad. The CPU is unchanged; duel core, 1GHz. But, it features a new quad core GPU. There was one reason for the A5X upgrade. The new retina display.
The iPad 2 was incredibly fast an smooth and the A5 processor inside of it is even more powerful then the popular Nvidia Tegra 3. Because the New iPad has four times as many pixels as the iPad 2, it needs 2x the GPU performance in order to keep things equally speedy. Hence the need for the A5X with quad core graphics.
The iPhone simply does not have this issue. Graphics performance is top notch. Even if the resolution is increased to 1136 x 940, there will be little (if any) visual difference. This isn't to say that a GPU boost would be bad thing. But a 2x graphics improvement is simply not necessary for an iPhone.
The A5X consumes significantly more power then the A5. Even though the CPU is clocked at the same speed. One of the reasons for this is that the A5X has an overall die size of 166mm, while the A5 found in the iPhone 4s has a die size of 122mm. The larger the die the more prone it is to energy leakage and the less room there is for other system parts, such as; battery, modems, flash chips, ect. Additionally, the A5X separates the RAM from the rest of the SoC, leaving even less room for the other parts of the system.
It would be incredibly inefficient to put an A5X into the next generation iPhone as it would take up dramatically more space and use up significantly more power. All the while the A5 is currently performing brilliantly.
What Might Happen
a. Apple introduces the new iPhone and it will use a brand new A6 processor.
b. Apple unveils the new iPhone featuring a second generation A5 processor.
I know what your thinking, "What? A next gen A5? How would that work?" Let me explain.
When Apple introduced the 3rd Generation iPad they simultaneously cut the price of the 16gb iPad 2's by one-hundred dollars. While there are no marked difference between these iPad 2's and one's announced in the Spring of 2011, there is an announced one that Apple sneaked in. That difference is the SoC.
While the original iPad 2 and iPhone 4s both shipped/ship with A5's built on Samsung's 45nm fabricating process, the iPad 2's that ship currently are built on Samsung's 32nm process. The difference is 122mm (in total size) vs 69 mm (in total size.) Reports show that these new iPad 2's use as much as 15-30% LESS energy then the previous iPad 2s.
By simply building the 32nm A5 into the New iPhone Apple could improve battery life and make room for other system parts (LTE anyone?)
None of us can be completely sure what the new iPhone will be like. But, based on the reasons I've given above, I do not believe that the next generation iPhone will have an A5X SoC.