See yesterday’s 4-Core CPUs do not Leave Much Grunt for Other Tasks and Will the iMac Pro Be Worth The Cost?.
There are hints out there that the iMac Pro will be SLOWER than the 2017 iMac 5K, due to downclocked CPUs. And even if not downclocked, the Intel XEON lineup shows clock speeds well below the 4.2 GHz of the 2017 iMac 5K.. I’d like to present the table here, but its copyrighted, so look at the "Intel® Xeon® W Processors for Mainstream Workstations” sections.
The most likely CPU for the base iMac Pro is the W-2145, which runs at 3.7 GHz with Turbo Boost up to 4.5 GHz. It has quad-channel memory which ought to help close the gap to the base clock of the 4.2 GHz iMac 5K, which also turbos to 4.5 GHz. But my guess is that the iMac Pro be slower than the 2017 iMac 5K on most all tasks excepting those tasks that use 8/10/18 CPU cores efficiently and/or heavy use of the fast GPU.
It’s also lame that these CPUs support up to 512GB memory, but Apple allows for a maximum of 1/4 that. How exactly is a pro machine that can use at most 1/4 of the supported memory a pro machine? I guess the case wouldn’t have been as pretty for presentation or something. 8 slots instead of 4 would at least have allowed 256GB.
There is a huge gaping hole in Apple’s design: memory bandwidth. To “feed the beast”, e.g., a 8/10/18 core CPU, memory access can be a major performance bottleneck. While that same limitation applies to the 2013 Mac Pro, going to 18 CPU cores generates a lot of contention for access to memory. Not every task is memory intensive, but many tasks are. It might be wise for those who need a 10 or 18 core CPU to put off the iMac Pro until the Mac Pro, which might use a higher grade chip with 6-channel memory and a dual CPUs option. Also, very few programs use 8 cores efficiently, let alone 10 or 18. Know your own workflow.
Planning ahead courtesy ≠ Apple
I for one (speaking as a professional) am very unhappy about Apple keeping mum on the release date and especially the pricing for the iMac Pro. The only vague information is $4999 for some unspecified base configuration.
The tax year ends in 27 days, and to write off for this year requires that gear be put into service in this year. It’s offensive of Apple to announce it 6 months ago and now leave buyers twisting in the wind, unable to plan.
Alexey V writes:
Thank you for your for your thorough, well-written reviews and opinions – I have read most of your Mac articles, and have found them to be very helpful.
I cannot wait for Apple to finally release the new Mac Pro, but like you, lean towards a top of the line iMac 5K (with OWC RAM) for my needs, since I mainly use Lightroom, Photoshop, and AutoPano Giga. I am, of course, also curious about the iMac Pro, and have been reading about it both on your website as well as on multiple other resources.
You may have already heard about this, but the 8-core iMac Pro may ship with a custom "W-2140B" Xeon CPU, clocked at 3.2GHz, as opposed to the W-2145, clocked at 3.7GHz. I am afraid that if the Geekbench results below are real, that model will barely edge out the current 8-core Mac Pro (and may not be any faster than your machine with its 3.3GHz 8-core CPU):
I realize this is a rumor, but this website is frequently accurate (I've been reading it for over a decade) and if past Geekbench score leaks are any indication, these results are real. Additionally, I realize that Geekbench scores do not equate to performance in your specific tasks, but they do provide a glimpse of a machine's performance
So I am not holding my breath for the iMac Pro – as much as want it to be a modern version of the 8-core-plus 2013 Mac Pro in the iMac 5K enclosure (with improved thermals,) I think it will be more of the 2017 iMac 5K with extra lower-clocked cores for twice/thrice/n times the money. Sure, it'll benefit people rendering video in HandBrake and the like, but it won't help me with Ps/Lr.
What I am holding my breath for is the next revision of the iMac with 8th or 9th generation CPUs (the i7-8700K, which is already out and is a 6 core/12 thread SKU, or i7-9700K, which was recently rumored to have 8 cores and 16 threads – both having the same 95W TDP as the i7-7700K in your 2017 iMac 5K). And yes, a 32" 8K "Super Retina" panel (with 3x, as opposed to 2x scaling, a-la iPhone X) would be amazing, but likely won't happen until panels with that pixel density first trickle down to iPads and MacBooks, or ever.
That said, I realize that waiting for Apple to update a machine is an ungrateful task, so I may break down and get the 2017 iMac – that is one heck of a machine for a photographer.
MPG: it’s a shame to have to choose faster for tasks A/B/C but slower for tasks X/Y/Z. Compromising the fundamentals is not elegance, never can be, and Apple ought to know better.
Methinks that a pretty computer case that looks good in marketing promotions has killed the iMac Pro for not just expansion (memory seems to be built-in and non-upgradeable), but also substantially reduced its numerous professional tasks, turning it into a very very expensive machine that is optimal for only very specific workloads.
Form over function triumphs again at Apple. I’m a bit sick of hearing how great a designer Jonathan Ive is (as clearly he is). But I consider it as a sort of idiot-savant designing to not have expandable memory, and to have to downclock the CPU speed (and then to brag about the awesome thermal management: “we designed it badly for thermal, so we worked extra hard to make it work”). I would not say this or mind so much if Apple were honest about their goal of “pretty design” as a priority over functional design, but when the promotion of the iMac Pro talks all about its awesome computing capabilities, it’s a little nauseating to see a half-the-truth story promulgated with such fecklessness.