iM 4,1-14,4 iMac 27 (2011) ATI Radeon HD 4850 512 Mini DisplayPort to Mini DisplayPort

[Lady Titan]

Hello everyone! There is a problem connecting the iMac 2011, it has a video card from 2009 ATI Radeon HD 4850 512, I connect it with a Mini DisplayPort to DisplayPort cable to a Windows PC, should this work? The cable supports resolutions up to 8K, the ports are working, is it a problem with the cable or is there fine tuning? on the other end there is Windows 10 with an RTX 3060 12gb i3 9100 z390 a-pro video card.

The task is to connect as a second monitor to the Windows PC )))


Cable Mini DisplayPort DisplayPort v1.3 8K 30 Hz/Length 1.8 meters/Belsis/ MiniDP DP 8K@30 Hz/5K@60 Hz/4K@120 Hz/2K@144 Hz/ 2K @165 Hz/1080P/BW8806

Is the problem in the GPU or the cable?!!!

 

[Bigwaff]

Target display mode on the 2011 iMac requires Thunderbolt connections. Mini-display port isn’t supported as input. At least, that is what Apple says…

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

Target display mode is a feature available with certain older Mac models.

support.apple.com

 

[Lady Titan]

Target display mode on the 2011 iMac requires Thunderbolt connections. Mini-display port isn’t supported as input. At least, that is what Apple says…

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

Target display mode is a feature available with certain older Mac models.

support.apple.com

is it possible to connect specifically to windows 10 and if so, what kind of cable is needed? hdmi won't work? on the motherboard there is an input to tape-c marked 10 and I looked at it without a video signal, I will remind the motherboard z390 a- pro if you have any solutions, please let me know)

maybe there is an adapter that allows you to connect an imac to a PC

 

[Bigwaff]

maybe there is an adapter that allows you to connect an imac to a PC

It depends on you PC hardware. This article will be helpful... mind the mistake in Section "Check the compatibility of the iMac for monitor use", Paragraph 3 ... the statement should be "If your iMac is newer than 2014, we’re sorry. It just won’t work."

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[Nguyen Duc Hieu]

is it possible to connect specifically to windows 10 and if so, what kind of cable is needed? hdmi won't work? on the motherboard there is an input to tape-c marked 10 and I looked at it without a video signal, I will remind the motherboard z390 a- pro if you have any solutions, please let me know)

maybe there is an adapter that allows you to connect an imac to a PC

Yes, it's called HDMI to USB video capture card. HDMI port video out from the Windows PC, USB in on the iMac.

 

[DCBassman]

maybe there is an adapter that allows you to connect an imac to a PC

Just today, I tried this. The PC has a GT1030 GPU with DisplayPort out, so I bought a DP to mini-DP to try this with a 27" 2009 iMac. Worked perfectly. Audio works, brightness control via the iMac's keyboard, all good. The only extra step was toggling the iMac function keys. This meant the TDM command became Fn+Cmd+F2 instead of just Cmd+F2.
However, the 2011 iMac: I don't know if the same cable will work into a 2001 Thunderbolt port. I will try it.

 

[DCBassman]

I will try it.

Nope, need the proper cable. Have a proper Thunderbolt cable incoming, will see what happens with that.

 

[OverKnight]

View attachment 2296478​

Lady Titan,
Please help me understand. You have an iMac 27" 12,2 with a HD 4850 installed (like the image above suggests)? I'm being told that is impossible to put a 2009 HD4850 in a 2011. Still, I am trying to install this graphics card in my iMac 12,2 and I cannot get it to boot properly into the macOS High Sierra. Currently, I can only boot into safe mode where the card shows as installed correctly just like your image above.

To perhaps help you with your question, external displays will utilize the graphics capabilities of the GPU and the HD 4850 could be limited by drivers you have loaded. macOS High Sierra should have all the necessary drivers (KEXTS) for the ATI (AMD) 4000 series graphics cards, but there could be something missing that is causing your problem.

 

[Amethyst1]

Nope, need the proper cable. Have a proper Thunderbolt cable incoming, will see what happens with that.

Thunderbolt Target Display Mode will not work using a Windows system (or an Apple Silicon Mac) as a source.

 

[DCBassman]

Thunderbolt Target Display Mode will not work using a Windows system (or an Apple Silicon Mac) as a source.

And yet miniDP to DP worked fine on 2009 iMac with Windows as source. What's preventing Thunderbolt from doing this? I'm not disputing this, because I've just this minute been trying it with no-go. Very annoying.

 

[Bigwaff]

If your Windows PC supports DisplayPort protocol over Thunderbolt, it might work, but I’m pretty sure TDM over Thunderbolt only works with Mac OS.

 

[DCBassman]

If your Windows PC supports DisplayPort protocol over Thunderbolt, it might work, but I’m pretty sure TDM over Thunderbolt only works with Mac OS.

I couldn't make it work even with another Mac, also High Sierra. More research, or different cables, needed...