Quick–fire questions & answers
WHY DOES MY iMAC’S DISPLAY GO WONKY WHEN WARM?
Probably because the graphics card in your Mac is failing. As it warms up, the fault becomes apparent; it might register if you run hardware diagnostics. Sometimes, this can be tricky to detect, and Apple’s advanced diagnostics are required through an Apple store or service provider.
HOW DO I RUN HARDWARE DIAGNOSTICS ON APPLE SILICON?
This is different from an Intel Mac, where you start up holding the “D” key. Start up an Apple silicon Mac into recovery mode by pressing and holding its Power button until it’s loading Startup Options. Then, press and hold Cmd+D until it restarts, and the Diagnostics Loader menu appears.