Image via Blackmagic

What you need to know

  • macOS Catalina seems to be causing issues with eGPU setups.
  • AppleInsider has reported failures to boot and freezing when using some units
  • Most common problems affecting Mac mini and Radeon 570 and 580 eGPUs.

It appears that macOS Catalina is causing problems for users with external GPU setups. According to reports, certain combinations of Mac and eGPUs are experiencing issues including failure to boot up and freezing. As reported by AppleInsider:

Typical problems reported by many users include an inability to boot up the Mac with a display connected to the eGPU. If the Mac will start with the monitor attached, it immediately restarts. Others report their Macs freezing.

Our own direct testing can confirm that the problems are happening on a Sonnet eGPU with the Sapphire 570 card that was in Apple's own developer's kit from two years ago.

Through both our own testing and the reports of users, AppleInsider can report that Vega 56, Vega 64, and Vega VII cards in any eGPU enclosure of suitable power aren't impacted by the problem. Additionally, an eGPU installed and connected to a Mac, with the display connected directly to the Mac and not through the GPU will still accelerate workflows like video processing with no issue.

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The report notes that it seems likely the issue is tied to Polaris AMD card. Certainly Twitter is awash with reports of compatibility issues, including references to a buggy Polaris driver. The issues seem to be just a bug at this state, and it's likely to be patched up in an imminent Catalina update. However, you may want to consider holding off on macOS Catalina if you do use an eGPU, just in case..