Lack of eGPU support in M1 Macs may only be temporary

Mac with eGPU

As iDownloadBlog reported a few days ago, the new Apple Silicon-powered M1 Macs do not support external GPUs (eGPU), but that could be a temporary hiccup. That’s because macOS Big Sur has bee discovered to detect a connected eGPU over Thunderbolt 3, although it’s not exposed to the user or actually accessible for compute and graphics tasks.

According to tests conducted by Mac4Ever, corroborated by AppleInsider, the latest M1 MacBook Air, MacBook Pro and Mac mini models running macOS 11 Big Sur appear to detect both the connected eGPU enclosure along with the PCI-E card inside.

AppleInsider has more:

In plugging a Pro Display XDR into a Blackmagic eGPU inserted into a Thunderbolt 3 port, it was found the eGPU enclosure was still detected and functions. The display communicates with the MacBook Pro as normal, complete with video playback.

Additionally, AppleInsider has seen the Razer Core X and the Sonnet eGFX Breakaway Box identify itself properly to macOS with an assortment of cards, including the RX 590, Vega 64 and Radeon VII.

However, monitors connected directly the cards do nothing.

The Radeon 580 GPU included in the above enclosure isn’t actively being used for graphics acceleration, nor are any of the cards we’ve been testing. A lack of drivers is the most obvious reason for the lack of support, but oddities in how Apple has implemented Thunderbolt or external PCI-E addressing may also be contributing factors.

All of the above could be interpreted as a sign that although eGPU functionality is omitted from the initial Big Sur release, support may be coming in the future as an update to Big Sur.

Unless, of course, this is something that requires chip-level support, in which case a new M-series chip may be needed to enable eGPU support on future Apple Silicon Macs. Big Sur continues to support eGPUs on Intel-based Macs.