Capture 2018 saw the introduction of a new rendering engine based on DirectX for Windows and Metal for macOS. While there were several good reasons to transition to newer rendering APIs, what really forced the change was Apple's deprecation of OpenGL support.
Metal is a new rendering API and from a developer's perspective quite an exciting one as it offers fresh and promising takes on key parts of what a rendering could look like. Unfortunately, being new, there are still enough driver bugs around that have not yet been weeded out. This is becoming especially apparent now that we are attempting to push Metal further than we ever have with our upcoming Capture 2020 release.
As things stand at the moment, Mac users with AMD GPUs will not be able to benefit fully from some of the performance optimizations of Capture 2020. Furthermore, Mac users with Intel GPUs (as found in a lot of smaller MacBooks) will not be able to run Capture 2020 at all. The reason for this are bugs in Apple's Metal drivers for which Apple are not able to provide any workarounds.
We remain hopeful that Apple will be able to resolve these bugs with macOS updates in the near future, but in the meanwhile we find ourselves forced to plan for a release with limited Mac hardware support. Our efforts are currently focused on ensuring the Capture 2020 will function on Macs with AMD GPUs. GPUs from Intel and NVidia will likely be explicitly unsupported.
The situation we find ourselves in is most unsatisfactory. The improvements we have engineered for Capture 2020 could not be maintained in parallel with technology from Capture 2019 within the same product. Without any feedback or prognosis from Apple on the amount of time required from their side to find resolutions to the bugs in question we have chosen the optimistic path, hoping that the necessary macOS updates will come soon and make Capture 2020 available to all Mac users.