iPad Pro’s A9X chip die shot reveals 12-cluster GPU, lack of L3 cache and more


iPad Pro unboxing

The A9X chipset used by Apple inside the iPad Pro is an absolute beast that decimates every other mobile chipset. It even rivals some laptop and desktop class processors from Intel, which was unimaginable a few years ago.

However, the A9X chip has mostly remained a mystery. The only known details about the chip until now has been that it is a dual-core chip that is clocked at 2.26GHz and is based on the 14nm fabrication process.

Now, thanks to a die shot from Chipworks and some prodding around by Ashraf Eassa from Motley Fool, more details about the A9X chip is now available. While the exact specifics still remain unknown, the die shot of the chip does confirm that the A9X packs in a 12-core GPU from Imagination Technologies based on its Series 7XT GPU. This is likely a custom solution that Imagination Technologies built for Apple, like it has done in the past for the company’s ‘X’ series chipsets.

A9X chip

Interestingly, the die shot also reveals that the A9X chipset does not feature any kind of L3 cache, which is found on the A9 chip.  Ashraf explains that the reason behind this is the super wide memory interface on the A9X chipset that is capable of transferring data between chips at 2x the rate of the A9 chip. Additionally, the bigger thermal headroom and the expense of adding an additional level of cache on such an expensive and large chip likely made Apple decide against using L3 cache on the chip.

Size wise, the A9X chipset comes in at 147 sq. mm, which is a staggering 40 percent larger than the TSMC-built A9 chip found inside the iPhone 6s and iPhone 6s Plus. The increased die area makes the A9X chip more complex and expensive to manufacture.

In the end, Ashraf says that the A9X chip is the “most advanced mobile system-on-a-chip available today” with the absolute best performance in the CPU and GPU department. He even says that the chip team at Apple should be proud of coming up with a chip like A9X in 2015.

Ever since the introduction of its own custom designed A7 chipset, Apple has been the leader in the mobile SoC segment in terms of CPU and GPU performance. Even better, the company has been making huge improvements in the CPU and GPU performance department every year, which other companies like Qualcomm and Samsung have been unable to do.

[Source Fool]

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