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Using iMac computer as external monitor
- Thread starter Okansar
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I will mirror 2024 Imac to 2021 old Imac and it will be in extend mode. Is it possible?
In the past I have used screen sharing over Ethernet on a M1 Mac mini to 2011 iMac but works well via thunderbolt too. A hdmi dummy is needed for gpu acceleration, these cost around £5-10 on Amazon and has a frame rate of around 30fps. Your set up may be better with them both being apple silicon.
The good thing about it is you use both iMac's. You can view the shared computer in a window or full screen, share files with drag and drop share a clipboard and share a mouse and keyboard.
The good thing about it is you use both iMac's. You can view the shared computer in a window or full screen, share files with drag and drop share a clipboard and share a mouse and keyboard.
HobeSoundDarryl
macrumors G5
Modern iMacs are not meant to be monitors. Apple has practically walled them off from such utility. There were once iMacs with Target Display Mode which made it easy to use them as a display, but Apple "improved" upon that by evolving away from such consumer utility. 
I've seen some YouTube hacks that basically convert the guts of iMacs into the equivalent of an ASD but then it's no longer usable as a separate iMac because it's had hardware hacks applied to make it a "dumb" monitor. I don't know if any of those work with Silicon Macs. You might want to do some fresh searches on YouTube if you are interested in this option.
There's also Luna Display for a fee and Duet Display for a subscription.
I've seen some YouTube hacks that basically convert the guts of iMacs into the equivalent of an ASD but then it's no longer usable as a separate iMac because it's had hardware hacks applied to make it a "dumb" monitor. I don't know if any of those work with Silicon Macs. You might want to do some fresh searches on YouTube if you are interested in this option.
There's also Luna Display for a fee and Duet Display for a subscription.
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These use screen sharing which is supported in old Macs but you can just use Airplay to Mac. If there's too much lag, then you can create a point-to-point Thunderbolt network between the two to greatly improve bandwidth. I mean to try the latter from my Mac Studio to my iMac Pro - I just have to buy the cable.