Apple M1 Ultra: How Much Better Will It Be Than Lesser M1 Chips?
A pricey upgrade option for the new Mac Studio desktop, Apple's M1 Ultra processor is seriously elite silicon. See the improvements (and one potential drawback) you can expect if you splash out for it.
By Tom Brant
At Apple’s March 2022 event, the company’s M1 silicon muscled its way into added relevance on desktop PCs. Desktops are the original hardware that made Apple a household name, and the new Mac Studio desktop—and the M1 Max and M1 Ultra chips that power it—are the penultimate step in completing the transition away from Intel Core and AMD Radeon chips in favor of ARM-based processors that Apple engineers design in-house.
Those last steps will be bringing Apple silicon to the lone Intel/AMD holdout, the Mac Pro desktop, and (perhaps) to some differently sized iMacs. Apple has hinted that the Mac Pro move could happen soon, but in the meantime, there’s now a newly established hierarchy among Apple processors.
At the bottom is the Apple M1, which powers the MacBook Air, the entry-level version of the MacBook Pro, and the Mac mini. Next up are the more powerful M1 Pro and M1 Max, available on the 14-inch and 16-inch MacBook Pro models. And finally, there’s the new flagship, the M1 Ultra. It’s available only as an optional extra for the Mac Studio, a squarish 8-inch PC that evokes the old G4 Cube from 22 years ago, or at least a bulked-up, taller Mac mini.
Upgrading to the M1 Ultra isn’t cheap. Opting for a configuration of the Mac Studio with the M1 Ultra inside starts at a minimum of $3,799, almost twice the entry-level Mac Studio model’s $1,999 asking price. So let’s take a look at the improvements (and one potential drawback) you can expect if you decide to pull the trigger on Ultra.
More Dies, Better Communication
The M1 Ultra’s marquee innovation starts with a simple concept. The new processor is essentially two Apple M1s—specifically, the die of two M1 Max chips—fused together to create a single giant processor via a high-speed interconnect. On its own, this approach to semiconductor design is nothing new; AMD has used it for a while in certain Ryzen Threadripper chips, and other manufacturers have employed it in the past, as well. Some ultra-powerful Windows workstation PCs use two or more Intel Xeon processors with interconnection protocols for communication between them.
But fusing dies together can result in all sorts of inefficiencies, not the least of which is that the computer’s firmware and software must be tweaked to ensure that the apps you need to run can take advantage of full power of the enlarged semiconductor. Apple says it has avoided this teething problem with a concept called UltraFusion. It’s an interposer that shuttles instructions between various parts of the M1 Ultra at lightning speeds: 2.5 terabytes per second total bandwidth, according to Apple.
Besides reducing bottlenecks within the M1 Ultra processor, UltraFusion also disguises the entire combination of dies as a single chip, so developers don’t need to rewrite the code of their software to take advantage of the increased dual-die power. At Tuesday’s launch event, Apple said there’s never been anything like UltraFusion, claiming it quadruples the bandwidth of the leading competitive interconnect technology.
Twice the Cores for Twice the Price
The M1 Ultra chip uses 20 CPU cores, split between 16 high-performance cores and four high-efficiency cores. That’s a dramatic increase over the M1 Max and M1 Pro, both of which have just 10 CPU cores, eight of them dedicated to high performance and two to efficiency. Doubling the number of cores will go a long way to speeding up the processing time for your CPU-intensive tasks, and it’s also a convenient way to justify spending twice as much on an M1 Ultra-powered Mac Studio. But twice the core count isn’t actually as big a leap forward over previous M1 chips as it might appear at first glance; remember, it’s essentially two M1 Pro processors glued together.
It’s not just compute cores that are getting a boost with the M1 Ultra. The new chip also has a whopping 64 graphics cores, double the amount of the M1 Max and quadruple the amount of the M1 Pro.
Put all the extra cores together, and you get some extraordinary potential, especially with certain workflow types that don’t require maximum processing power for long periods of time. Apple claims that the M1 Ultra is 1.9 times more powerful than the latest 12th Generation Intel Core i9–12900K desktop CPU when both are running at the 60-watt power level.
Now, Apple’s initial claims on CPU performance are vague; the table above doesn’t delineate specific applications, conditions, or even what the scale at left really means. We’ll have to see how it shakes out in actual testing, but it’s safe to say that these performance claims are with selected applications running natively under M1, optimized for macOS and the M1 architecture.
128GB of Memory, Only if You Need It
Instead of the conventional way of doing things, where the CPU and GPU each address their own memory located in separate areas, say, of a motherboard and graphics card, the M1 chip addresses a single pool of memory it needs for both processing and graphics functions, and that memory is part of the SoC, for faster accesses.
This unified memory concept is also used in the M1 Ultra, but the new chip brings a new higher memory limit of 128GB. That’s an astonishing potential peak amount of total memory in what amounts to a mid-level workstation desktop, though you do have to fork out an additional $800 to bump up the memory from the 64GB amount that’s in the base M1 Ultra configuration. It goes without saying that you should only do this if you’re absolutely certain that you’ll be running apps that know what to do with more than 64GB of memory.
The Thermal Question: Watch Out for More Noise?
The trifecta of a larger processor with more cores and more memory isn’t without possible drawbacks. Other than making the M1 Ultra version of the Mac Studio expensive versus the M1 Max flavor of the machine (though not as dear as the Mac Pro or some competing Windows workstations), it also brings the inevitability of more heat and the necessity of a more powerful cooling system to dissipate it.
Apple says it has carefully designed the Mac Studio’s cooling system to prevent the desktop from being audible during most workflows. But the fact remains that if you push the M1 Ultra to its limits (which you should, if you’re shelling out the cash for it), you’re going to hear the fan activity. How loud will it be? Probably not excessively loud, if the whisper-quiet but still-audible cooling systems of preceding Macs like the 27-inch iMac are any guide.
Still, the presence of any fan at all actually makes it a step backward from the Mac Studio’s ancestor, the G4 Cube, which needed no active cooling system at all. Stay tuned for our observations once we get the Mac Studio in-house for some intensive bench-testing calisthenics.
Originally published at https://www.pcmag.com.
