Archive for December 12, 2017

Tuesday, December 12, 2017

The iMac Pro

Joe Rossignol:

Apple today announced the iMac Pro will be available to order on Thursday, December 14. Pricing starts at $4,999 in the United States.


With four Thunderbolt 3 ports, the iMac Pro can drive two 5K displays or four 4K displays at 60Hz simultaneously. It also has a 10 Gigabit Ethernet port, four USB-A 3.0 ports, an SD card slot, and a 3.5mm headphone jack.

Joe Rossignol:

Brownlee in his hands-on video said the high-end 18-core iMac Pro will ship early next year, alongside an unannounced 14-core model that will apparently be added to the lineup for a total of four Intel Xeon processor configurations.

Marco Arment:

iMac Pro reviews are out! Great! I’m excited! Let’s go!

But we still can’t order them or even view their configurations, pricing of every option is still a mystery, and only the lower half of the CPU options will be available at launch.

I miss clean launches with no asterisks.

Apple doesn’t consider developers “pros” for PR purposes. It’s pretty much always and only video editors.

Even though we’re a FAR bigger industry that probably buys more pro Macs, PR likely thinks nobody wants to see Xcode builds or VM containers. They’re probably right.

David Heinemeier Hansson:

I spoke with the iMac Pro team yesterday and they’re keen to change this, they said. Developers is the biggest pro group for them. I did give them shit for failing to press that point and for the flubs like TouchBar. Hope they listen!

Cabel Sasser:

Apple (amazingly/unprecedentedly?) provided me with a loaner iMac Pro a few days ago to check out, and in turn, I’m very eager to share my notes with you. Here are six initial impressions in a thread[…]

We tried compiling one of our meatier Xcode projects on the iMac Pro (10-core Xeon W, 3 GHz) vs. our standard Mac Pro (3.5 GHz Xeon E5, 6-core). Sure, the Mac Pro is old, but the iMac Pro compiled the project 41% faster. A pretty sincere boost.

I would like to see a comparison with a 2017 iMac. iMacs, and even Mac minis, have outperformed Mac Pros at compilation for a while now.

Craig A. Hunter:

Most of my apps have around 20,000-30,000 lines of code spread out over 80-120 source files (mostly Obj-C and C with a teeny amount of Swift mixed in). There are so many variables that go into compile performance that it’s hard to come up with a benchmark that is universally relevant, so I’ll simply note that I saw reductions in compile time of between 30-60% while working on apps when I compared the iMac Pro to my 2016 MacBook Pro and 2013 iMac.

That’s actually rather underwhelming for development. There’s a much bigger performance difference for video stuff.

Colin Cornaby:

I will say this about the iMac Pro: Even though I’m holding out for the Mac Pro, it’s the first Mac in a while that in theory could actually meet my needs.

Mark Damon Hughes:

The specs on this are actually top of the line, it has sufficient max RAM (128GB!), the AMD Vega card is a great choice. We’d have to wait to see benchmarks between the 10-core, 14-core, and 18-core models for ideal multi-core vs single-core performance.

That said, this isn’t the machine I want. Non-expandability is a massive problem for these machines. Wrapping a high-end CPU inside a tight thermal enclosure like the iMac is not great, no matter how much ventilation you put out back; and fans running right behind your screen and speakers is awful, it needs to be on the floor or far end of a desk.

I’m glad the iMac Pro exists, but I don’t think it makes very much sense for the type of work I do. It’s so much more expensive than a regular iMac for seemingly little benefit.

Previously: My 2017 iMac, The 2017 iMacs.

Update (2017-12-13): No word yet on whether the keyboard is bendy.

See also: John Voorhees.

Russell Ivanovic:

“Spec out a similar PC and you’ll see the iMac Pro is priced reasonably!” 2 issues:

1. I’d never build a PC like that. I’d pick consumer graphics and consumer parts. It would be half the price and better for my needs.

2. The iMac will still cost that a year from now. The PC won’t

What I actually want is a desktop Mac I can put consumer parts into and upgrade. Shocking. I know. The iMac 5K doesn’t have the CPU and GPU I want, and I can’t ever change that.

Colin Cornaby:

This is kind of an issue with the iMac Pro. Want a consumer CPU with a nice GPU? Nope. The iMac doesn’t have nice GPUs and the iMac Pro doesn’t have consumer CPUs.

I think the iMac Pro would have made a hell of a lot more sense with 6 and 8 core i7s and a 10 core i9 instead of going to Xeons. Use Vega GPUs. Much lower starting price, more options, fills an actual hole in the Mac lineup. Doesn’t compete with the Mac Pro.

Such an iMac Pro would have been a lot more interesting to me.

Rob Art Morgan:

Here’s an interesting tidbit: Geekbench OpenCL Computer Score for Pro Vega 64 in 2017 iMac Pro = 169397. Score for RX Vega 64 in 2010 Mac Pro = 184835. (Both running macOS 10.13.2)

Colin Cornaby:

And the Mac Pro is already handicapped on Vega 64 because of the slower CPU. So that’s a positively dismal showing for the iMac Pro.

Basically: If you care about graphics performance, wait for the Mac Pro. Which is where we started to begin with.

I suspect Apple at some point realized that the iMac Pro wasn’t going to be a sustainable replacement for the Mac Pro for reasons like this. If this was the Mac Pro replacement, people would be leaving the platform with performance like that.

Honestly with those scores you’d literally be better off buying a 2013 Mac Pro and throwing a Vega 64 in an eGPU box.

Update (2017-12-14): Rene Ritchie:

You can’t upgrade RAM yourself but you can take it to an Apple Store or certified service center and they can upgrade for you.

Marco Arment:

Sure, but only by Apple service places, and probably therefore only Apple RAM, and definitely therefore at Apple RAM prices.

So technically, yes, but probably not the way people want when they ask for “upgradeable RAM”.

Paul Haddad:

128GB upgrade $2400 vs [$1432.95]


Introducing the Apple T2 chip, our second-generation custom Mac silicon. By redesigning and integrating several controllers found in other Mac systems — like the system management controller, image signal processor, audio controller, and SSD controller — T2 delivers new capabilities to the Mac. For instance, the T2 image signal processor works with the FaceTime HD camera to enable enhanced tone mapping, improved exposure control, and face detection–based auto exposure and auto white balance. T2 also makes iMac Pro even more secure, thanks to a Secure Enclave coprocessor that provides the foundation for new encrypted storage and secure boot capabilities. The data on your SSD is encrypted using dedicated AES hardware with no effect on the SSD’s performance, while keeping the Intel Xeon processor free for your compute tasks. And secure boot ensures that the lowest levels of software aren’t tampered with and that only operating system software trusted by Apple loads at startup.

Update (2017-12-15): Jason Snell:

It’s a big milestone. This is almost four years to the week that Apple last released a professional desktop Mac, with the release of the redesigned, cylindrical Mac Pro. Since then there’s been… nothing, other than the grousing of high-end Mac users concerned about the lack of updates.

Matthew Panzarino (via Phil Schiller, Hacker News):

The messaging was interesting to me. It was absolutely, clearly, a love letter to developers.

Rene Ritchie:

The definition of pro has grown and expanded over the years. […] Once upon a time, it was graphics and publishing, and then eventually video and sound professionals, that defined the category. Now, developers are by far the biggest group.

Samuel Axon:

While the iMac Pro offers much faster compile times (2.5 times the other iMac in some cases), the multiple cores create some impressive multitasking opportunities, too. In one use case demonstrated by Apple, a 10-core iMac Pro was set up to run three simultaneous iOS instance tests, multiple virtual machines, and other tasks including regression testing—all while working with a large project in Xcode with no slowdown.

Lance Ulanoff:

Apple also wanted to make it clear that the iMac Pro is also a developer’s tool and demonstrated how a 10 Core iMac Pro can simultaneously handle three iOS simulations (on screen was what looked like screens for an iPhone 8, an iPad and iPhone X all running the same application), a Linux Ubuntu VM serving Apache PHP code, a, yes, Windows 10 virtual machine running 20 Chrome browser sessions, and a virtualization of the previous Mac OS, without missing a beat or making loud wheezing sounds. Seriously, I didn’t hear a peep from the system.

The iMac Pro has performed some of the fastest compiles Apple has ever seen.

I would hope so! Apple’s page shows Build Time benchmarks of a 10-core iMac Pro being 1.9x the speed of a top-of-the-line 5K iMac at compiling Clang/LLVM/compiler-rt. The 18-core iMac Pro is 2.4x. (Rene Ritchie says that he saw a demo of a 10-core iMac Pro that was 2.4x.) These are much more impressive numbers than Craig Hunter and Cabel Sasser reported (above). I would guess that Apple’s numbers are less representative of what Mac and iOS developers would see because they don’t focus on Objective-C or Swift code, and Swift compilation benefits less from multiple cores.

Gabe Weatherhead:

It’s a very reasonable price for what the iMac Pro delivers so I’m not moaning about the price points. It seems very fair but here’s the price rundown for an entry level iMac Pro and and a comparable iMac 5K[…]

Paul Haddad:

The base modela are never that bad of a deal, its once you start adding in the extras that it starts getting ridiculous.

Marco Arment:

If Xeons are pointless to you, you’re not an iMac Pro customer.

The real argument from the “iMac Pro is overpriced!” camp is usually, “Apple won’t make the consumer gaming PC I want.”

And that’s a good argument to have. But that doesn’t mean this Xeon workstation is overpriced.

Colin Cornaby:

It looks like the iMac takes a 10-20% hit in GPU horsepower compared to the same retail Windows part. Vega 56 should be 10.5 TFLOPS. Vega 64 should be 12.66 TFLOPS.

Lloyd Chambers:

What Apple has done is to ‘spin’ form over function as top-notch engineering for heat management. By designing too small an enclosure (very poor decision for heat removal) it then became necessary to use top-notch engineering to deal with the heat problem which would not exist if a proper-sized case had been used. And that would make the iMac Pro less svelte—and form takes precedence over function. The disappointing kicker is to realize that Apple is using downclocked (slower) CPUs because the faster ones would generate too much heat because the decision was made to make a too-small enclosure for the iMac Pro and/or not to size up the venting and fans. Gorgeous engineering visually (!), but impaired performance and non-upgradeable memory.

Paul Haddad:

The base clock on the 8 core is 700MHz lower than it should be and boost is 300. The 10 core’s base is only 300 lower and boost is spot on.

Seems like they are handicapping the 8 to sell more of the 10s. If you are going to buy one the 10 is definitely the one to get.

Lloyd Chambers:

When only 1 to 4 cores are used (common in my own Photoshop usage), the fastest clock speed wins, e.g., the 2017 iMac 5K has a base clock of 4.2 GHz and turbo boosts to 4.5 GHz, so none of the cores drop below 4.2 Ghz. The iMac Pro 8-core has a base clock of 3.2 GHz and turbo boosts to 4.2 GHz, the 10 core has a base clock of 3.0 Ghz and turbo boosts to 4.5 Ghz. But when more cores are used, the iMac Pro CPUs drop towards base clock speed—much lower than the 2017 iMac Pro. Hence there is some average clock speed for the number of cores used that determines which machine wins, and this is not likely to be the iMac Pro until 6+ cores are used.

John Gruber:

Second, and to me far more importantly: how committed is Apple to keeping the iMac Pro up to date? It’s an impressive piece of engineering — do not let the appearance fool you into thinking that the iMac Pro is just an iMac with a dark finish and speed-bumped processors. Internally, it’s a completely different architecture. But the 2013 Mac Pro was an impressive piece of engineering and design that Apple put a lot of effort into, too.

My hope is that the iMac Pro has been designed with the future in mind.

See also: Accidental Tech Podcast, Hacker News, Mac Rumors, Josh Centers.

Juli Clover:

If an iMac Pro becomes unresponsive and requires restoring, like if there’s a power failure during a software update, there are a special set of instructions iMac Pro users must follow, which require a secondary Mac.

As outlined in an Apple Configurator 2 support page, an iMac Pro restore requires a second Mac running macOS High Sierra with internet access and Apple Configurator 2.6 or later installed.


This restore process is similar to what must be done for an iPhone or iPad that is unresponsive, and it is necessary due to the extra security afforded by the Apple-designed T2 chip.

Stephen Hackett:

All security measures must be weighed against the inconvenience they cause. Personally, I don’t think this tips in the wrong direction, but I know many will disagree with me.

(I assume that disabling Secure Boot doesn’t do anything to make a restore possible without a second Mac and a copy of Configurator.)

Users with bricked iMac Pros aren’t going to know how to do this, unless they are super nerdy. That may not be a big deal now, but I think it is safe to assume this sort of thing will trickle down to consumer-oriented Macs at some point. That’s not to mention the headaches this may cause in the enterprise.

It’s not clear to me what benefits we are getting from Secure Boot.

Update (2017-12-20): Apple (via Vas):

iMac Pro computers don’t support starting up from network volumes.

Update (2017-12-22): See also: Accidental Tech Podcast.

Update (2018-02-19): See also: Gabe Weatherhead, Samuel Axon (Hacker News).

Update (2019-01-28): Michael Kummer:

The table below illustrates the significant differences between the Late-2014 5K iMac, the 2017 5K iMac, and the first-generation iMac Pro. Throughout this iMac Pro review, I have based any specifications of either the 2014 5K iMac or the iMac Pro on the models I own.


Additionally, the iMac Pro runs incredibly quiet, and I have never heard the fans spin up while performing regular work or exporting video footage from Final Cut Pro X.


So is the iMac Pro worth the money for folks like me, who don’t honestly need the multi-core performance Apple’s pro desktop computer delivers? Probably not. In fact, I would likely be just as productive with a traditional, fully spec’d out 5K iMac. However, I decided to go with the iMac Pro anyway because it offers me more room to grow and thus, potentially, improves its longevity.