I've noticed graphics performance problems and glitches on my iMac 13,1 (21.5", Late 2012) if my external display is set as the "primary" as picked by dragging the menu bar to it in Display Arrangement.
The problems seem to go away if the iMac's internal display is primary. This didn't happen with Sierra and prior MacOS versions. Has anyone else noticed this or is it just me? I'd really prefer the much bigger 24" display to be the "primary" and the iMac itself to be "secondary", like I've had it set for years.
The problems seem to go away if the iMac's internal display is primary. This didn't happen with Sierra and prior MacOS versions. Has anyone else noticed this or is it just me? I'd really prefer the much bigger 24" display to be the "primary" and the iMac itself to be "secondary", like I've had it set for years.