2018 15" MacBook Pro (RP560X) [8th,6C,H] + RX 5700 XT @ 32Gbps-TB3 (Mantiz Venus) + macOS 10.15.1 & Win10  

System Specifications

• MacBook Pro 15" (2018)
• CPU: 2.6 GHz Intel Core i7 (i7-8850H)
• GPU(s): Intel UHD 630, Radeon Pro 560X
• macOS 10.15.1 [19B77a] & Windows 10 [18362.295]

eGPU Specifications

• Mantiz Venus 550W -> 600W Corsair SF600 Upgraded
• Powercolor Red Dragon AMD Radeon RX 5700 XT
• Apple TB3 Cable

Installation

The installation process is usually straightforward for this Mac.

For macOS

Native compatibility: This eGPU setup has official support since macOS 10.15.1 Beta 2 [19B77a] on TB3 Macs and does not require any additional software-work to get working. It is also easy to connect multiple such eGPUs.

Not all applications take advantage of external GPUs. For that, one can use set-eGPU.sh or Prefer External GPU option in Mojave or later.

For Windows 10

If you are using Windows 18362.329 or newer, downgrade Windows to 18362.295. I recommend using the 295 build. Please refer to this thread for more information.

The setup process is simple:

1. Download a copy of AMD drivers from bootcampdrivers.com (my build was with: September Edition drivers).
2. Use DDU to uninstall Apple-provided drivers. It is recommended to do so in Windows Safe Mode.
3. Boot back into Windows normally and install the downloaded drivers.
4. Once the Radeon Pro 560X is up and running, hot-plug eGPU.
5. eGPU may already start functioning as is. Your setup is complete. In other cases, it should default to Error 12.
6. If you see error 12, uninstall the Display Adapter from Device Manager > Displays.
7. Reboot with the eGPU plugged in. All displays should be active.

Benchmarks

Let me preface by apologizing for the shoddy screenshot dimensions. Messed 'em up.

LuxMark 3.1:

macOS	Windows

Unigine Heaven at Extreme HD (same as 1080p 8xAA Ultra):

macOS Internal Display	macOS External Display	Windows Internal Display	Windows External Display

Interestingly, OpenGL on Windows performed poorly vs. macOS (OpenGL default). Also note that on Windows, the GPU was overclocked, so the difference is greater:

Additionally, I was unable to test the OpenGL benchmark on the internal display. I experienced some other interesting symptoms: With all displays active, eGPU performance suffered on the internal display and the benchmark lagged. I had to disable the displays connected to the eGPU. After running my benches, I re-enabled my eGPU-connected monitor and tried a game. The game stuttered. Only a restart fixed the issue. Finally, looking at just Valley benches, we see approximately 20% eGPU performance loss by rendering on the internal display. For some other loads and games, this might be higher or lower.

Comments

Compared to my Vega 64, I see a slight regression in OpenCL compute performance on macOS. However, OpenGL and Metal performance exceeds that of Vega 64, plus we are likely to see some driver optimization over the next few macOS releases.

On Windows, I was able to overclock the GPU via MSI Afterburner. Power +50, 2150 MHz Core, & 920 MHz Mem. GPU-only power consumption never exceeded 220W in preliminary testing. Performance in the worst case similar to Vega 64, but in most cases, higher.

The Powercolor Red Dragon AMD Radeon RX 5700 XT is one of the best air-cooled XTs in my opinion because of it's understated design, 2 x 100mm fans (better than 3 x 80mm fans area-wise), true 2-slot design, and silence. The dual BIOS allows for some experimentation as well. I run it on the OC BIOS. Combined with the Corsair SF600 PSU and Noctua case fan for the Mantiz Venus, this is probably the most powerful and quietest eGPU setup I've ever had, running virtually silent in all scenarios, while being well-supported in both OSes.

Update: Two Red Dragon's have already failed on me. For the time being, I do not recommend this model for eGPU use.