I've been using a new program called RetinaRelay[0] to use my 5k iMac as a second display for my M1 Macbook using an ethernet (or Thunderbolt for even better performance). Works brilliantly. It's definitely higher latency than a normal monitor (my ethernet connection is 45ms vs 5ms for a monitor) but it's not noticeable for coding and miles better than remote desktop or similar.

[0] https://www.retinarelay.com/

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steinvakt2 6 hours ago | parent [-]

Cool, I suppose it doesn’t work with windows? To use a 5k iMac as monitor to my windows desktop?

	▲	bytesmith 5 hours ago \| parent [-]
		I'm pretty sure it relies on Mac APIs like Metal and ScreenCaptureKit but it's worth reaching out to the developer. He was very responsive when I requested features, and it may be a lot easier to build a windows application that adheres to the protocol using agentic development.