Photographer’s review of the 2018 Mac mini 6 Core i7 – Do you need an eGPU?

I occasionally like to write a blog post that is helpful to photographers in general. I recently decided to sell my 5k 27” iMac and upgrade to a 2018 Mac mini 6 Core i7. Until 2018 the Mac mini was really slow and not something a professional photographer with large Lightroom and Photoshop images would really want to use. However, things have changed significantly, with the latest 2018 models. The Mac mini is now a very powerful desktop class computer with some exceptions I will discuss below.

What’s great about the new Mac mini 2018 for photographers

Mac mini 6 Core i7 Geekbench Scores
Mac mini 6 Core i7 Geekbench Scores

The new 2018 Mac mini can now be configured with a 6 Core 3.2Ghz Intel Core i7 8th Generation desktop class cpu for $1299. This is a high-end powerful desktop cpu that blows away the performance of the previous laptop class chips.  In fact, this is approaching the power of the new iMac Pro and blows away some of the older Mac Pro desktops. Thanks to the new cooling system this actually runs a lot quieter than my older iMac.  Lightroom used to really kick up the fans of my iMac especially when importing or exporting images. You can see my Geekbench scores here, this cpu is fast!

Another great feature of the new Mac mini 2018 is the upgradable ram. It’s not the easiest thing to do, but if you are careful and purchase the proper tools, the ifixit guide is pretty easy to follow. The main problem I had was popping the motherboard out from the case, it really takes some force to break loose the clips so be careful! I purchased my 6 Core i7 model with the base 8GB of ram and 256 SSD. I upgraded the unit to 32GB of ram using this kit from crucial.com and it works great!  You want a minimum of 16GB of ram or more to use Photoshop and Lightroom together, I’ve tested and it works best with 24-32GB of ram. You start to get a lot of memory pressure and swapping with only 16GB.  Lightroom is a memory hog.

I don’t worry anymore about the size of the internal SSD storage in my desktop Mac. I do not keep my Lightroom catalog or the camera raw cache on it. The only thing I keep on the internal storage is the applications themselves which take up a small amount of space. For the Lightroom catalog, camera raw cache, and the generated previews you want very fast storage. With the thunderbolt ports it’s easy to get very fast external storage. I use the very reasonably priced 1TB Samsung T5 and it works very well, I get around 500mb/s read and write speeds. While not nearly as fast as the internal Mac mini storage, it’s plenty fast enough to run Lightroom perfectly.  You won’t notice the difference at all.

For my 15TB of photos I use a Drobo 5Dt raid. While this is much slower with its spinning hard disks, it doesn’t really affect the speed of Lightroom much, as long as you generate 1:1 previews and smart previews when importing the pictures into Lightroom. All the previews load quickly from the 1TB Samsung external SSD, then Lightroom can pull data from the Drobo only if needed. I see a lot of people complaining about slow Lightroom performance, but if you use a setup like mine it really is quite fast.  I can move through and adjust images with little to no delay.  If you need any Lightroom performance tips let me know in the comments.

What’s terrible about the new Mac mini 2018 for photographers

Everything sounds great so far right? I’ve seen it said on other sites that you don’t need a powerful GPU ( graphics card ) for Lightroom and Photoshop. Many of Photoshop’s and most of Lightroom’s tools don’t even take advantage of powerful graphics hardware.  This might be true for a single small monitor like a laptop display, but not for a large 4K multi monitor setup like I have!

Mac mini connected to three displays through eGPU
Mac mini connected to three displays through eGPU

I thought the integrated Intel HD 530 graphics in the 2018 Mac mini would be fine, it supports 4k and 5k displays so it should be great.  I was so wrong about this! I guess I don’t have the greatest eyesight, but on my 32” 4k monitor everything is too small for me when running in native 4k mode.  The Mac has a great solution for this, it scales everything so it still runs in native resolution, you see all the pixels in your images, but text and the user interface look like they are running on a lower resolution display. For example my display is running in true 4k, but everything is being scaled to look like the size of things on a 1600p display.

Resolution scaling of 4k display on the Mac
Resolution scaling of 4k display on the Mac

The way the Mac does this (see image) is it actually scales everything up to an even higher than 4k resolution then back down for the display.  The important thing to know is the graphics in the Mac are actually having to process 6016×3384, much higher than 4k, to display the scaled resolution on my 4k display.  I also have 2 other 1440p displays attached as well.  This is putting a huge stress on the graphics processing.  This is just way too much for the integrated Intel graphics to handle.

I couldn’t believe how poorly Lightroom and Photoshop ran initially on this Mac mini.  Lightroom was usable although zooming in and scrolling around images was extremely jerky.  Photoshop was almost completely unusable. For example, if using a clone brush, the delay and lag of the brush was so bad it was nearly impossible to use. I knew there was no way I could work like this.

eGPU ( External Graphics Processing Unit ) to the rescue

Gigabyte RX 580 Gaming Box connected to Mac mini 2018
Gigabyte RX 580 Gaming Box connected to Mac mini 2018

In the past year Apple started embracing external graphics card enclosures that could be plugged in directly to the Thunderbolt 3 ports on newer Macs. I decided to see if an eGPU would solve my performance problems. It most certainly did! At first I purchased a large Sonnet eGFX Breakaway Box and a AMD Radeon RX 570. This was just very large and I had an issue with the unit locking up. Then I discovered the Gigabyte RX 580 Gaming Box. Of course I’m not buying this for gaming, but it’s a powerful external Radeon RX 580 with 8GB of ram in a very tiny enclosure. The Gigabyte RX 580 Gaming Box is perfect for me. It’s not much larger than the Mac mini itself, it’s normally very quiet, and it has 3 Displayport connections and one HDMI.  I tested it and all the ports can be used at the same time.  In fact I have 3 monitors on my desk and a 4k TV hooked to show clients pictures all at the same time. Try that with any previous Mac!

How is the performance now?  It’s fantastic, the graphics card makes all the difference. Lightroom zooming, scrolling, adjustment brush and even moving through images is very quick and has almost no lag at all.  All my issues with the clone brush, zooming and scrolling and other common filters in Photoshop work perfectly now.  While Lightroom and Photoshop are very CPU dependent, they also need powerful graphics to work on high-resolution displays.

How do I get a Wacom tablet to work with an eGPU?

I’m still having a few strange bugs like once Lightroom completely stopped accepting mouse or Wacom input and required a restart.  Also the Wacom drivers don’t really support eGPUs, their drivers never seem to work correctly with new Mac OS releases.  If you have any displays connected to the Mac mini internal ports, the Wacom tablet will only be usable on those displays and not any displays connected to the eGPU. However, if you only have eGPU displays connected, the Wacom tablet will lock to your main display. This is ok for me, but it could cause problems if you are using an eGPU with a laptop.  How can Wacom be so bad at this?

To sum all this up.  The 2018 Mac mini is fantastic computer for a photographer.  Just upgrade the ram yourself and purchase the smallest storage from Apple. Everything else can be connected super fast over Thunderbolt 3.  Also, an eGPU is required, unless you are running on a single low resolution display.  I really can’t believe how poor the Intel integrated graphics perform in Adobe apps and the Mac desktop in general on a 4k display.  I hope you find this article useful if you are thinking about using the 2018 Mac mini for photography!

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