Our biggest burning question about Apple’s ARM silicon

Our biggest burning question about Apple’s ARM silicon

For years, Apple has steadily revealed how the ARM-based chips in its mobile phones were catching up in performance to the beefier silicon you’d find inside a laptop or desktop — in 2018, the company claimed its new iPad Pro was faster than 92 percent of portable PCs. At some point, it seemed inevitable that Apple would turn the more efficient chips into the primary processors for its Mac computers, too.

Now, it’s official: Apple is migrating the Mac to its own homegrown silicon, starting later this year.

But are Apple’s ARM chips actually powerful enough now to replace the likes of Intel and AMD? That’s still an open question — because at Apple’s 2020 Worldwide Developers Conference (WWDC), the company shied away from giving us any definitive answers.

a handful of canned demos and vague promises

This time, the company’s typical array of charts, benchmarks, and “fastest ever” claims for each new generation of homegrown ARM silicon were completely MIA. Apple wouldn’t chat about it when we asked. Even a prerecorded chat with one of its silicon architects didn’t provide much insight. Instead, the company showed a handful of canned demos and made some vague promises that the future might be faster.

The closest we got to a comparison was effectively, “is machine learning faster with hardware acceleration turned on?”

Admittedly, we weren’t expecting Apple to hand us an ARM-powered Mac during a pandemic, and the prerecorded demos during the keynote and subsequent “State of the Union” address were moderately impressive. Using the same Apple A12Z Bionic chip you’ll find in an $800 iPad Pro, the company showed that a low-power ARM desktop can already handle a variety of power user apps on Mac, including:

Versions of Microsoft Office, Adobe Photoshop, and Lightroom running natively on ARM Three streams of simultaneous 4K Pro Res video in Final Cut Pro Rotating around a photorealistic stone face in Cinema 4D Rotating around a 6-million polygon scene in Autodesk’s Maya animation studio, with textures and shaders on top Rendering effects in the Unity game engine The games Shadow of the Tomb Raider and Dirt: Rally running on Mac smoothly (but at low-ish resolution and detail) Dirt looked… well… a little messy.

What’s more, Apple’s ARM-powered Macs will be able to automatically translate some existing Intel apps thanks to Apple’s Rosetta 2 conversion software: while they looked a little ugly, both Shadow of the Tomb Raider and Dirt: Rally were running that way, as was Autodesk Maya.

But for the most part, Apple seems to be asking developers to take its word that ARM will unlock “a whole new level of performance,” without discussing how that performance actually stacks up right now.

Maya seemed like a more impressive demo, though I don’t have a good frame of reference.

The company’s press release says very specifically that Apple’s new chips will “give the Mac industry-leading performance per watt,” and that’s a very deliberate turn of phrase. Apple’s arguing that by building the most efficient kind of chips it can — “the highest performance with the lowest power consumption” — it can achieve more raw performance by tipping the scales of that performance-per-watt formula toward more watts.

In other words, if you build a MacBook Pro-sized chip with a MacBook Pro-sized heatsink and enclosure, plus a MacBook-sized battery, your iPhone-esque processor theoretically has room to do a heck of a lot more work. But it’s almost always been true that ARM-based processors are more efficient than the competition, and the scales don’t tip on their own. Speeding up a chip isn’t just a simple matter of giving it more juice — you’ve got to design a beefy enough processor (or, say, the world’s fastest supercomputer) around that efficient architecture, and Apple isn’t bragging that it’s actually done that yet.

You may remember Intel’s Core M / Y-series chips, which wound up in the thinnest MacBooks, also began with Intel touting their relative efficiency — but they wound up starting off slower than their mainstream Intel counterparts and only became a worthy choice after a few more years of work. Perhaps the iPad Pro’s A12Z Bionic would make for a more powerful MacBook than Intel’s current low-power laptop chips, but Apple isn’t saying so; maybe it’ll take a later chip in Apple’s roadmap.

It also seems telling that Apple isn’t publicly planning to get rid of Intel anytime soon. Not only is Apple planning to release several additional Intel-based Macs in the future, but the company “will continue to support and release new versions of macOS for Intel-based Macs for years to come.” For a company that prides itself on the “courage” to often make a clean break with the past, it’s a little unusual. (Then again, this isn’t a product launch; it’s a developer conference.)

All that said, Apple does say we should expect pure performance — not just efficiency — in one category in particular: graphical performance. Apple writes that the ARM initiative will also give the Mac “higher performance GPUs,” including additional horsepower for games, and it showed off a few apps (Affinity Photos, Unity, the aforementioned Cinema 4D, and Dirt: Rally) taking advantage of Apple’s Metal framework to fire instructions directly to the GPU.

While that might not satisfy gamers used to having a dedicated Nvidia or AMD graphics chip, Apple’s integrated graphics might actually be a substantial boost over the Intel integrated graphics that ship in, say, a new MacBook Air. There’s also the possibility that Apple’s talking about building beefier GPUs of its own — though Apple isn’t talking about whether its CPUs will interface with laptop chips from AMD or NVIDIA, much less desktop GPUs or external GPUs right now.

And it’s true that not everything is about performance, anyhow. Apple is promising its ARM-based Macs will be able to run more kinds of apps than before, thanks to both native iOS app support and hardware-accelerated machine learning chops built into the silicon. They’ll be able to “keep cached cloud content fresh for days” even when your Mac is asleep, and Apple says using your iPad as a secondary monitor for your Mac will get better thanks to the image processing that Apple’s already built into its ARM chips. Though Apple didn’t provide any metrics, the company suggests ARM will provide more battery life, too.

Right now, Apple’s most important task is to convince would-be buyers that — this time — ARM chips won’t require them to abandon their old apps or make other unacceptable compromises in order to switch.

Apple needs you to know it isn’t pulling a Windows RT — so far, so good

That’s the message that Apple tried the hardest to nail at WWDC, and it feels like the company is making good headway. It’s got Rosetta to automatically translate some of your apps, while a handful of key developers like Microsoft and Unity are building native versions of others. Apple’s developer sessions showed that — theoretically — creating a “universal” app for multiple platforms is as easy as pressing a button. Apple showed off file system and network access, virtual machines and peripheral support, the ability to natively play a game with an Xbox controller, and even a promise to let you boot from external drives with ARM-based Macs.

Watching Apple’s WWDC keynotes, it’s easy to imagine there might be no downside, no “legacy” apps you’ll need to abandon; just a whole bunch of extra iPhone and iPad apps you can now additionally use by upgrading to an ARM-based Mac.

But it feels very strongly like there’s something Apple isn’t telling us about performance, and we’ll need to wait to see. Improved performance is one of the most compelling reasons to buy a new computer, and an absolute requirement for pros. Performance is time, and time is money, after all.

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