Using Imac as a external monitor for windows laptop

Apple listed DisplayPort input as a feature of the 27" Late 2009 and 27" Late 2010 iMacs. From those models' Technical Specifications:

"27-inch models also support input from external DisplayPort sources (adapters sold separately)"

I could be wrong, but I don't think that the Technical Specifications of any Thunderbolt-equipped Macs mention TDM. Any iMac that has TDM and Thunderbolt ports requires Thunderbolt input. When Thunderbolt was fairly new, that would have ruled out many other Macs, and virtually all PCs, as potential signal sources.

When the first 27" 5K Retina iMac came out in Late 2014, Apple dropped TDM. Neither that iMac – or any iMac released after it – can act as a TDM display.

Nope, the iMac is a computer and does not have a video input port.

iMacs are computers, they are not displays for other devices. If you need an external display for your PC please buy one.

Do you not realize the value in having a factory color graded monitor for the value of the 2009-2010 models as an external display

It is not necessary for us to realize the value. We are not Apple employees; we hold no influence over them. An Apple employee will NOT see your comment here, but will see your concerns if your use this feedback link:

Feedback - iMac - Apple

However, as Apple removed the TDM capability from iMacs nearly a decade ago, and removed the ability for other Macs to be the video source for the limited iMacs that had TDM capability in Early 2020, it seems likely that any request today is late to the party.

TDM was ALWAYS Mac-to-Mac. Apple never intended, supported, nor documented it for use with Windows or other devices. The article that kaz-k links shows the very restrictive hardware and macOS version issues with TDM when it was a feature.

I've used TDM with a TDM-supported iMac and a TDM-supported Mac. It was not that great. My setup did not support extended desktop, knocking its usefulness down several notches.

Hi,

If your Windows laptop has mini display or thunderbolt port, it could be possible, though if it doesn't, you can't.

Use your iMac as a display with target display mode - Apple Support

I understand your frustration however my original statement "iMacs are computers, they are not displays for other devices." is and will remain correct. You made no mention of wanting or needing a Calman certified monitor and I am very sorry that I forgot to pay my 2024 dues to the world wide Mind Reading Association.

If you don't like my posts, please feel free to simply ignore them like I plan to ignore you.

I see this advice from your account on almost every page asking this question. Do you not realize the value in having a factory color graded monitor for the value of the 2009-2010 models as an external display? For a Calman certified monitors the cheapest being on the market is roughly $280 which is plagued with issues. Next budget friendly one is $600. Some people are seeking this option for a budget friendly monitor with a wonderful display.

[Edited by Moderator]