Apple 2017 iMac 5K is a Terrific Machine, but Too Often It Impedes My Work
Have a similar performance issue? Consult with Lloyd.
I previously wrote about issues facing my workflow and various performance issues in:
- Understanding Thunderbolt 3 Bandwidth
- Understanding Thunderbolt 3 Daisy Chaining
- My Days of 4 CPU Cores Are Over: Six Cores is Dubious for My Work, 8 CPU Cores Might Have to Be the New Minimum + Might Need 8TB SSD
When I see myself waiting many times a day for a too-slow machine and having to cable and cable things just to get backups done, I start looking at what I can do to eliminate time-wasting bottlenecks.
I previously covered my CPU core issue as per above, but it’s only half the problem.
My Thunderbolt 3 daisy-chaining problem
In my work environment, the 6-device limit is a serious limitation. It means unplugging some devices anytime I want to do a different backup or do some kind of TB3 or USB-C test. Crawling under my desk to do that no fun, and prone to disconnect already-connected devices. Then the change has to be undone when finished. Just last night I could not work because I had to unplug my scratch drive while some backups were in progress.
I maintain a high level of redundancy for backups, and I often like to make several backups at once. With a daisy-chain, doing that means every last device has to be powered-on to get to the last one in the chain. But that is too many devices (more than 6 total), so nothing works, so that means unplugging the chain at device #4 or #5, and recabling for the desired device. What a PITA.
My core setup as of today requires a minimum of three (3) Thunderbolt 3 devices:
- OWC Thunderbolt 3 Dock — essential for its Mini DisplayPort output.
- OWC Thunderblade — my new silent main store.
- LaCie Bolt — 2TB SSD for working files and scratch
- Daily “everything” backup (OWC Thunderbay 6, always attached though not powered on continually)
- Primary “everything” backup (OWC Thunderbay 4, always attached though not powered on continually)
- Secondary backup <== have to plug / unplug things to do use it!
OWC Thunderbolt 3 Dock (2nd one)not possible Secondary backup #2not possible USB-C OWC Mercury Elite Pro Mini Dual, so have to use a regular USB 3.1 gen 1 port not possible Testing something (USB-C or Thunderbolt 3)not possible.
What do do
As a photographer, I work and travel up to 3 months a year in my Mercedes Sprinter van. This drives certain requirements which are non-negotiable. My minimum operational requirements are:
- 64GB memory. This is not enough at times, but 90% of the time it is adequate.
- 2TB internal SSD. This is mandatory so that I can quickly setup and do core work without having to connect the OWC Thunderbolt 3 Dock and/or OWC Thunderblade. Plus it matches my 2TB SSD backups.
- Built in 5K display of good size e.g. iMac 5K. Having to buy a 5K display and cable it to a Mac mini (frequent setup/teardown in my van) and then lose half the TB3 bandwidth on that bus is not a winning idea.
The 2018 MacBook Pro is a non-starter for its 32GB memory limit and tiny screen. The 2018 Mac mini has no display, so it’s a setup hassle. Which leaves only the 2017 iMac 5K or 2017 iMac Pro as options.
Buying into old technology in an untimely manner is not what I want to do, but I am increasingly considering selling my 2017 iMac 5K and going for a discounted or refurbished 2017 iMac Pro (now 15 months old, due for a refresh). Why Apple is sitting on its hands for a 2019 iMac 5K is unclear, but there are CPUs with 8 cores that are suitable for it, and surely it would come with dual Thunderbolt 3 busses and a better GPU as well.
Alan G writes:
I concur with your article about the limitations on the current line up. Although I primarily do workstation music production, I also have huge loads and processing going in and out simultaneously for a variety of tasks and backups
I had the 2017 iMac 5K for over a year and it served me well, but I started finding the limits as you have and was so let down that a 6 core never materialized.
I bit the bullet and even though I thought that a new iMac may be not that far off, I spent some pretty big bucks on a iMac Pro 10 core with 64 ram and 2TB SSD and Vega 56. Hooked up with a Thunderbolt 3 SSD-only enclosure. The differences, while not immediately drastic, start to become visible pretty quickly where bottlenecks of prior work seems to never happen, or at least much less frequently or to a lesser degree.
My point is, that your thinking is justified. As you have tested iMac pros before, I’m sure you have seen this to some degree. The extra TB3 room, the extra CPU cores and more capable cooling become very clear. I am happy that I made the switch and although will be tempted by any upgrade as I always am, I can see this holding me for a while.
All that said, this is Apple and not without it’s share of core rot as you like to say. The Apple T2 chip is problematic at best. There are many threads about T2 chip caused bridge os reboots on MacBooks and iMac Pros. I get those. Not constant, but on occasion. I have turned off as much as I can to get rid of T2 functions that might spur this error on. (turned off secure boot in recovery mode, turned off File Vault, turned off Siri, turned off sleep (except monitor). This keeps the T2 problems to a minimum.
That said, the affected people seems to be small or maybe under reported, but there are some huge threads on this problem that have gone for over a year in many cases unresolved. Just keep that in mind. Mine was from November and still had the issue. (primarily at startup or reboot only and not in the middle of work thankfully)
MPG: I’ve heard of those Apple T2 chip issues, and they concern me.
2018 MacBook Pro: the T2 Chip Can Erratically Kernel Panic the System
At this point I will probably just wait for new revisions of the iMac and/or iMac Pro, which might possibly offer 6K displays. With luck, the iMac will have 8 CPU cores and it ought to have dual Thunderbolt 3 busses like most all other recent Macs.