Apple has made changes to graphics drivers and Metal in Mac OS 12.3, among other things to enable GPU acceleration in the Blender 3D software. Unfortunately, it also seems to have led to bugs that cause it for some users.
Namely, users have started reporting graphics-related issues on Macs with AMD graphics cards. The problems seem to apply to cards in the Navi family (Radeon 5000 and 6000 series) from manufacturers other than Apple. This applies to cards used directly in Mac Pro (2010 and 2019, in egpu chassis with other Intelmacs and also in so-called hackintosh home builds.
The problem These include greatly reduced performance (almost halved results in Geekbench’s Metal test), problems in individual programs such as Apple’s Motion, bugs in GPU-based functions such as decoding of heic images and choppy / slow user interface.
We have also seen reports about problems using more than one external monitor after the update, but it is unknown if it is related to the above.
Hackintosh users have discovered that the error may be due to Apple’s drivers not filling in the correct information about the affected graphics cards and that the system can therefore not make full use of the cards. A temporary solution that can also benefit users with old Mac Pro (2010 model) is to manually add the missing data via the bootloader program Opencore.