Late 2018 Mac mini + RX [email protected] (Breakaway Puck) + macOS 10.14.1 & W10 1803 [theitsage]  


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November 9, 2018 3:50 pm  

Following my teardown of the 2018 Mac mini, I've been testing different eGPU configurations. Nvidia eGPU as expected was straightforward in Boot Camp. I'm glad to find AMD eGPU can work in Windows as well without encountering error 12. The Sonnet Breakaway 560 was chosen for this build because of its tiny footprint. It's about half the volume of the Mac mini. All four monitor outputs from the RX 560 were used to power one 5K and two 4K monitors.


System specs:

2018 Mac mini - i5-8500b/UHD Graphics 630 iGPU/16GB RAM/256GB SSD


eGPU hardware:

Sonnet Breakaway Puck + RX 560 + .5m Thunderbolt 3 cable


Display hardware:

  • One HP Z27q 27-inch IPS 5K - connected via two DisplayPort cables
  • Two LG 27UD69P-W 27-inch IPS 4K FreeSync - connected via one DisplayPort and one HDMI cable


Hardware pictures:


Installation steps:

In Windows 10 1803, the good news is this 2018 Mac mini has Large Memory allocation. This helps with resolving error 12 (not able to find resources for eGPU). Viewing from the backside of the Mac mini, the two right-sided TB3 ports connect to PCIe x4 Controller 1909. The two left-sided TB3 ports connect to PCIe x8 Controller 1905. PCIe x16 Controller 1901 is unoccupied in my Mac mini. I'm guessing this is reserved for the 10GbE which my system does not have. I have had good luck with connecting AMD eGPU to the Controller 1909 in my 2016 15" MacBook Pro so I hot-plugged the RX 560 eGPU to the Thunderbolt 3 port closest to the Mac mini's HDMI port.

Windows could detect the Thunderbolt 3 enclosure and eGPU via hot-plug. After Radeon graphics driver installation, I had to restart the system in order to use the RX 560 eGPU. During the setup process, I connected the monitor to the Mac mini's HDMI port. Prior to booting back into Windows with the attached eGPU, I switched all monitor outputs through the RX 560 eGPU. This is due to the Mac firmware's tendency to deactivate the Intel iGPU when there's other GPU(s) present. I could not see the boot screen but all three monitors came on once Windows got to the login screen and Desktop. I also installed Intel Thunderbolt Software [] to learn more about Thunderbolt configuration. You don't need this software in a Mac running Boot Camp in order to use Thunderbolt devices. Apple set the Security Level in the firmware to SL0 - No Security. Here we see two Titan Ridge Thunderbolt 3 controllers hosting two ports each.

In macOS 10.14.1 it was plug-and-play. This is a pleasant surprise because the RX 460/560 never had native eGPU support. This is a new addition to 10.14.1. The 5K + dual 4K monitor arrangement worked very well. Here are screen captures of Graphics/Displays and Thunderbolt tree in System Information

I ran CL!ng to check the connection bandwidth of both iGPU and eGPU in macOS.



In macOS, I ran Luxmark to compare the performance gain the RX 560 provides over the Intel UHD Graphics 630 iGPU. Also to note is that the iGPU can only output to either two 4K @ 60 Hz or one 5K @ 60Hz max. This RX 560 eGPU ran one 5K and two 4K monitors concurrently with ease. You can connect a few more monitors through the USB-C/Thunderbolt 3 ports if needed.

In Windows, I ran Unigine benchmarks. We're seeing a 4-5x performance gain in gaming. The Sonnet Breakaway Puck 560 is not quite capable of handling AAA titles but eSports should be good.

Intel UHD 630 iGPU Radeon RX 560 eGPU



The 60% base price increase is a sticker shock. Seeing the components packed inside this latest Mac mini, it's hard to come away unimpressed. This system was built with eGPU in mind. Don't overspend on the Blackmagic eGPU though because there are many good options available for much less. My one complaint with the base i3 configuration is the insultingly low capacity of the soldered SSD.

Best ultrabooks for eGPU use

eGPU enclosure buying guide

82 external GPU build guides

Noble Member Moderator
Joined: 2 years  ago
Posts: 1489
November 9, 2018 5:04 pm  

@itsage Interesting tidbit about macOS 10.14.1 supporting RX460. Apple has not updated their support document regarding this at this time at least.

Also, your eGPU perf. numbers (H2D, D2H) seem to be much lower:
Troubleshooting eGPUs on macOS
Command Line Swiss Knife
Multiple Build Guides

theitsage liked
Active Member
Joined: 11 months  ago
Posts: 12
November 9, 2018 7:43 pm  
Posted by: theitsage

Following my teardown of the 2018 Mac mini, I've been testing different eGPU configurations. Nvidia eGPU as expected was straightforward in Boot Camp. I'm glad to find AMD eGPU can work in Windows as well without encountering error 12.

Hi all and @itsage,

I'm glade to read that.
I'm thinking switching from my MBPr mi-2015 (TB2) to a Mac mini setup.

About NVidia eGPU:
- you're saying it is straightforward. I tough that Apple does not fully support eGPU in BootCamp. Isn't it? There is no limitations in BootCamp now? No patch needed  (eGPU EFI boot loader) ?
- In MacOS, without Nvidia web drivers, it's a no go at the moment. Di you achieved something ?

Thanks you all

Hardware: MacBookPro11,5 (15 Retina, i7 4980HQ) dGPU R9 M370X + TB2/TB3 adapter + Razer Core v2 + GTX 1070 Ti
Software: macOS high Sierra 10.13.6 (17G65) + Web Driver 387. + 1.4

Active Member
Joined: 8 months  ago
Posts: 6
November 9, 2018 8:40 pm  

I sincerely appreciate you writing up these tests! I have a 2017 iMac 21.5" with the rx560 dGPU. I have tired every version of Windows 10 with every EFI bootloader, edited DSDT, etc with no luck. Error 12 with my Gigabyte rx580 gaming box every time. I think this will be the push to sell the iMac and pickup a Mac mini. iMac is perfection on MacOS, but I want to be able to play my games without a tower! 

Thank you for sharing this!

Eminent Member
Joined: 2 weeks  ago
Posts: 29
November 10, 2018 12:50 pm  

@itsage thank you for the write-up. I was planning on opting for the 10GbE as I may need it in future. Would this complicate things at all in terms of setup and it taking up resources? If so I may just go without it.