Apple A8X chip Secret: The first three-core processor

The IPad and iphone processors are sometimes identical and sometimes different. Last time, the iphone 5S, the ipad Air was A7, only a low frequency of 100MHz, and this time, the iphone 6/plus, ipad Air 2 is a dual-core A8, the other is a three-core a8x, which is the mobile industry's first three cores processor.

For some reason, chip expert Chipworks has not released a8x microscopic observation report, so there are still many places can not be fully determined, but basically also sorta.

CPU: Maverick three-core

First of all, it's big. The A8X integrates about 3 billion transistors, half more than A8, and three times times more than the A7 of the first generation. The core area is not proportional to the number of transistors, but it can be roughly estimated that the a8x should be greater than a6x 123 square millimeters, or even close to a5x 165 square millimeters, and is expected to become the second largest chip in Apple's history.

Of course, it is also 20nm, theoretically from TSMC, but it still has to wait for the final confirmation.

2011 The first self-designed A5, Apple has always adhered to dual-core, and now finally added another, with the enhanced version of the cyclone 64-bit architecture, while the frequency is also slightly increased than A8 100MHz and came to 1.5GHz.

The Geekbench test showed that the single-threaded performance of the IPad Air 2 was nearly 12% higher than the iphone 6, which even exceeded the frequency boost, indicating further enhancements to the A8X architecture.

Multithreading performance has improved by 55%, and the third core has been perfectly released.

Apple's official view is that A8X CPU performance has increased by 40% compared to A7, but in fact this is still very conservative, more multi-threaded applications, Geekbench 3 score increase of 68%, of course, for multicore insensitive applications will not be so high.

GPU: Six cores It's not going to run.

There is still no precise message on the GPU side, but there is only one option depending on the 2.5 times-fold performance boost: Imagination's six-core flagship product PowerVR GX6650.

The first guess on the IPhone 6 would be it, but eventually it was discovered that the quad-core enhanced version of Gx6450,ipad Air 2 should be no more wrong.

The 2.5 times-fold increase in Apple's mouth is relative to A7, thanks to the enhancement of the quad-core to six-core, 6XT-series architecture and, of course, the frequency boost.

On the other hand, the screen resolution of the IPad Air 2 is still 2048x1536, which means that the demand for display performance has not increased significantly, and the quad-core GPU has proved enough to drive such a high-resolution screen in the last year, adding to the six-core significance?

Interestingly, the IPad Air 2 has a screen pixel value that is just over half the 50%,GPU core of the iphone 6 Plus, which means they can display similar content at native resolution. Apple has been sparing no effort to push the tablet game, and the IPad Air 2 will be the best tablet for the game.

Memory: Finally 2GB.

Apple has been "stingy" in memory, and the IPhone 6/plus and 1gb,ipad Air 2 are finally "epoch-making" on the ground 2GB.

The frequency is still lpddr3-1600, but the bit width is back to the 128-bit (the previous generation has cut half to 64-bit), so the bandwidth is as high as 25.6gb/s, which can feed the six-core GPU well.

This may also be the cause of the 2.5 times-fold performance spike, after all, there will not be any occasional bandwidth limitations like A7.

The CPU cores on the a5x and a6x are not able to access the full memory bandwidth because half of it is reserved for the GPU. A7 introduced 4MB three cache, Cpu/gpu shared, memory bandwidth is no longer isolated, the CPU can basically use all the bandwidth.

The same is true on A8X (can run full 25.6gb/s), the level three cache is still 4MB, which can be confirmed from memory bandwidth testing, but because the level two cache is larger, the three-level cache will be used later.

Thanks to this, the memory latency of the A8X is also lower.

Stronger architecture, more CPU/GPU cores, higher frequencies, greater bandwidth ..... A8X with about 1 billion transistors to complete another sublimation.

Apple A8X chip Secret: The first three-core processor