The iPad Pro's chip is not a big deal

The iPad Pro is here, and it comes with a lot of promises. The most-repeated is that its A9X chip is a desktop-class processor that fits inside a tablet. Initial benchmark results confirm that this is by far the most powerful chip Apple has ever put inside an iPad, leading some to suggest that Apple's A9X is now at the same level as Intel's laptop chips. This could change the PC and laptop industry forever, apparently, with popular Apple commentators suggesting that "the future belongs to ARM, and Apple's A-series SoC's are leading the way." To put it lightly, that's a bit premature.

With the iPad Pro, Apple has created a tablet with more power than ever before. But there's no magic or witchcraft to this feat; it just made a bigger tablet. The larger the object, the more room to dissipate heat, and the more space for a bigger battery. It's basic physics, and the iPad Pro takes full advantage. It contains a 38.5Wh battery. That's 40 percent larger than the battery inside the iPad Air 2, and about the same as the company's 11-inch MacBook Air and 12-inch MacBook, not to mention Microsoft's Surface Pro 4.

It's often vaunted that ARM-based chips are more power efficient than those based on Intel's x86. That's just not true. ARM and x86 are simply instruction sets (RISC and CISC, respectively). There's nothing about either set that makes one or the other more efficient. And despite ARM chips like Apple's typically being ultra-low power, the A9X is clearly not. Its performance on various sites' battery tests show comparable endurance to the 12-inch MacBook. Ars Technica's 200 nits WiFi browsing test, for example, shows the iPad Pro lasting three hours less than a MacBook. A WebGL test from the same site shows the iPad Pro outlasting the MacBook by two and a half hours. Of course, the iPad Pro's screen is slightly larger and denser than the MacBook's, and the two run completely different operating systems. The point isn't to discern which is more efficient, but merely to say they have similar battery sizes, similar endurance, and therefore similar efficiency.

But what of the benchmark tests that show the iPad Pro outperforming Intel's Core M processor, and even coming close to Intel's MacBook Pro range? Don't believe them. Patrick Moorhead, a highly respected analyst with a strong background in chips, urges caution, especially when it comes to comparing GeekBench numbers, as many have. "GeekBench is a synthetic, mobile benchmark," Moorhead tells Engadget. "The benchmark code is more like mobile application code than it is desktop code." Using GeekBench to test A9X versus Intel chips is "like comparing apples and oranges or an SUV with a sedan on the straight-away," he explains.

One area where the A9X has advanced massively over previous Apple chips is in graphics performance. "This has nothing to do with ARM and everything to do with PowerVR and Apple's implementation of PowerVR's IP," Moorhead clarifies. PowerVR is a graphics company that develops architectures and licenses its IP out to many manufacturers. It's not ARM; it's not x86. Intel licenses PowerVR tech, and straight-up features PowerVR designs in its Atom line.

Intel's Iris graphics have made massive leaps in recent years -- that's why we have Retina MacBooks without discrete graphics cards, but clearly Apple is doing good things with PowerVR's IP. The jump forward in power this generation is not really the result of a huge architectural rethink, but rather the lessened thermal constraints of the larger iPad Pro and the slow reduction in power usage for all chips -- ARM and x86 included -- due to manufacturing improvements.

What Apple has done, then, is create a powerful tablet chip, one with a processor that addresses the ARM instruction set and a graphics component that utilizes PowerVR technology. It's not a leap forward, and it's not out of nowhere; it behaves and performs exactly as a chip with as high a clock rate and as large a power draw as the A9X should do.

The idea that Macs could be running ARM chips has been around for a long time. Microsoft launched Windows RT, a version of its OS that works with ARM chips, because it wanted manufacturers to create devices that could compete with the iPad. It didn't work, mostly because of Window's reliance on legacy applications, but also because Intel started taking its low-power programs more seriously, and poured money into them. Its chips caught up fast. All the low-power Surfaces now use Intel x86 chips, rather than the Nvidia ARM chips they launched with.

Apple doesn't have such a large legacy to support -- it only moved to Intel chips nine years ago -- but there would be no perceivable benefit to switching an existing x86 platform to ARM. "I do not believe ARM-based chips will be powering Macs in the next few years," said Moorhead. "I do believe Apple will attempt to scale up the iPad Pro even further, which could potentially eat into Macbook sales."

Intel is continuing to pour money into low-power chips, like the Core-M found in the MacBook. Apple and Qualcomm (the largest ARM manufacturer) will obviously continue to develop new and better chips, but there's no telling if Qualcomm will be able to keep pace with an Intel running at full pelt, and it doesn't make business sense for Apple to get into an arms race there. In fact, you could argue that it's more likely that Apple would create an iPad Pro with an Intel chip than a Mac with an Apple chip. Intel really wants in on Apple's iOS business, and if it reaches its goals for the next few years, why should Apple continue to design its own chips? It's a useless expense.

According to Moorhead, Intel came close to putting one of its chips inside the iPad Pro. "[The iPad Pro] business is open to both Apple's own ARM-based AX chips and Intel," he explained, "Intel is fighting hard to get that business and I believe almost had [the iPad Pro contract] with the new Skylake-based Core M had it been available earlier." That new Core M is coming next year, and is far more likely to form the foundation of the second-generation MacBook than an Apple chip. Whether it might form the foundation of an iPad one day is down to Intel's ability to deliver on its promises, and Apple's willingness to extend its reliance on the company beyond the Mac.

- Source: Engadget