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2018 Mac Mini [8th,6C,B] + RX 6600 XT @ 32Gbps-TB3 (Sonnet Breakaway 650) + macOS 12.0 & Win10 21H1  


Mini i5
Prominent Member
Joined: 2 years ago

System specs 

2018 Mac Mini, 3.0 GHz Hex-Core Intel i5, 32 GB RAM, 256 GB SSD, iGPU : Intel UHD 630

Mac OS Monterey 12.0 and Windows 10 21H1

eGPU hardware

Sonnet Breakaway Box 650 + AMD Radeon RX 6600 XT (XFX Speedster Qick 308)


Dell 27" 4K connected via Display Port cable



AMD's Radeon RX 6600 XT doesn't cost thousands, draws a moderate 165 watts of power, and easily fits inside that enclosure already perched on your desk.

(Unlike certain cards... cough, cough... RX 6900 XT


Hardware Pictures 

BB 650
6600 XT in BB
Ports XFX


Installation steps 

The Speedster Qick 6600 XT, like most XFX gaming cards, is typically swole. Its appearance makes an impression (facts). But with the card being only 10.8 inches in length, the effort involved in installing the 6600 XT and re-assembling my Breakaway Box 650 was nothing but minimal.


MacOS Performance

(Waiting on the release of Monterey 12.1)


Bootcamp Windows Setup

So I’ve been ride-or-die-ing alongside the latest version of Windows 10 21H1 for awhile now, and I’m pleased to report the Win 21H1 eGPU road trip continues to be a velvety-smooth, pothole-free, thoroughly enjoyable excursion.

In fact, this multi-month-long journey’s been going so well, now I even trust 21H1 to install all of those pesky, periodic Windows System Updates automatically.

Yep, that's right. Some serious Windows 21H1 Bootcamp staning is going on here.

To prep for my new RX 6600 XT, I booted into Windows 21H1 (with my eGPU powered off, and the Mini directly connected to my Display)

Win Ver


And downloaded the 6600 XT driver and Radeon Software from AMD

AMD driver page
AMD driver update


I ran the AMD software installer until it finished, and the expected "Oops" message appeared.

Installer Message


I closed the installer window, and Shut Down Windows from the Start menu.

I disconnected the HDMI cable between my Mini and my display. I connected the 6600 XT to my Display via DP cable.

I set the Sonnet BB power switch to ON. Then powered on the Mini.

I watched the Redmond-curated photo of your next island getaway appear on my display for a second or two. Then the display went black - meaning error 12 had taken root.

So, I powered off my Mini, and powered it back on again.

I repeated pressing the Mini's Off/On button until another island photo reappeared and remained on my display.

Each time I powered the Mini "On", I of course waited a couple minutes for Windows to boot up completely, before powering OFF. 


So, to TLDR, getting the 6600 XT running perfectly in Windows required restarting my Mini (5) times. 

That is a couple more on/off cycles than was needed before with a 5500 XT card, but relative to the kind of slogging Error 12 fosters on other Macs, it remains a very easy series of steps to accomplish.

Device Manager
Radeon software info



Windows Benchmarks

Performed at High Quality settings using DirectX and OpenCL.


Unigine Superposition 4K: 6,380 (47fps)

Basemark GPU

Basemark GPU 4K: 7,636 (76 fps)


Geekbench OpenCL: 65,572

Fire Strike 1440p

DX11 Fire Strike 1440p Graphics Score: 23,601

Fire Strike Ultra 4K

DX11 Fire Strike Ultra 4K Graphics Score: 6,333

Time Spy 1440p

DX12 Time Spy 1440p Graphics Score: 7,564

Time Spy Extreme 4K

DX12 Time Spy Extreme 4K Graphics Score: 3,775

Port Royale 1440p

Port Royale Raytracing 1440p: 3,556


Direct X Raytracing 4K: 11fps (cringing emoji level)


The Analytics-minded crowd would comment here how the 6600 XT is able to run neck-and-neck with last-gen's 5700 XT series, but the 6600 XT gets there while enjoying better energy-efficiency, thermals, and noise levels along the way.

I'll just say that the 6600 XT def passes the eye-test. This Navi 2 card is pretty good at smoothly moving a bunch of pixels across your screen. The 6600 XT is a fun card to have if your focus in Windows is pure entertainment and not something like super-aggro competition. I see the 6600 XT as primed for membership in the well-regarded "if you know, you know..." club.


Windows Blender Rendering Performance  

Before taking a look at OpenCL compute rendering, a bit of fun comes from opening the Eevee Race Spaceship demo file - as this is a case of the actual reality matching Eevee's promised excellent real-time viewport performance. With the 6600 XT, rotating around the ship and zooming into fully-rendered details really couldn't feel any smoother.

Eevee Race Spaceship

Race Spaceship (artist: Alessandro Chiffi / ONdata Studio)

Now, here's some fresh OpenCL GPU luv from (Summer 2021's) 2.93 LTS for Windows using Blender's native Cycles rendering engine. (Sample quantity and light ray depth tweaks made for speed + image quality)

Italian flat

Italian Flat (artist: Flavio Della Tommasa)

Render time using Cycles OpenCL denoising and clamping: 2 mins 35 seconds 

Monster under the bed

Monster Under the Bed (artist: Metin Seven)

Render time using Cycles OpenCL denoising and clamping: 0 min 23 seconds

Car demo

BMW Car Demo (artist: Mike Pan)

Render time using Cycles OpenCL denoising and clamping: 1 min 27 seconds


Classroom (artist: Christophe Seux)

Render time using Cycles OpenCL denoising and clamping: 1 min 24 seconds

Nishita Sky Demo

Nishita Sky (artist: Creative Commons CC0)

Render time using Cycles OpenCL denoising and clamping: 2 min 23 seconds


Windows Gaming

I'll say here for now that Star Wars Squadrons at 4K, and Control at 1440p are a blast (literally) to play on the 6600 XT.

Hopefully I'll be able to go more into the FPS of it all some point soon. One small bug with the current Radeon software, though, is its FPS counter metric is...ah, currently unreachable at this number.



Otherwise, Good times 😎

2018 Mac Mini + AMD RX 6600 XT (Sonnet Breakaway Box 650) Monterey 12.1 pending + Windows 21H1

2018 Mac Mini [8th,6C,B] + RX 6600 XT @ 32Gbps-TB3 (Sonnet Breakaway 650) + macOS 12.0 & Win10 21H1 [build link]  

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