iMac 5k and using a second monitor with it - resolution

Hello AlphazBet,

For the iMac with Retina 5K display, it can support its native display of 5120 by 2880 pixels and still support an additional monitor of up to 3840 by 2160 pixels. So for what you are asking it will support that monitor without any compromise in the main screen's resolution.

iMac (Retina 5K, 27-inch, Late 2014) - Technical Specifications

http://support.apple.com/kb/SP707

Regards,

-Norm G.

Hey AlphazBet,

No problem with the assist.

Take Care,

-Norm G.

I just bought an LG UM95 which is a nice wide 4k monitor. I am still waiting for the 5k iMac to get here, but I am assuming I will use a Thunderbolt cable to connect them. My question is, how many 4k displays will the new 5k iMac drive? Just one?

Hey norm123,

I just got my imac 5k and have it connected to my late 2009 imac using thunderbolt cable. My understanding is the late 2009 imac is a mini display port and is compatible with the cable. I am trying to use the 2009 imac as a second screen to my 5k imac, but I am having trouble with how to switch the late imac into second screen mode. Another site said to hit command and F2 but that doesn't do it. Any suggestions? I really would like to complete this set up.

Thanks

I have exactly the same question - want to use my old late 2009 iMac as a second screen to my new 5k. Can I use a male mini display port to male mini display port cable, and hit command and F2?

I believe you should be able to; might be command-fn-F2 depending on how you're using your function keys and which keyboard you have on the old iMac.

And I believe the the cable has to be mini display port to mini display port, even though a port might be Thunderbolt. See Target Display Mode: Frequently Asked Questions (FAQ) - Apple Support

Hello, I just came across this post, as I just purchased a new iMac retina 27 inch. I am trying to use my late 2009 iMac as a second display using a mini display port. I can get it to work my old second monitor, but when I try the 2009 mac, and I press command F2, it shows the options to set up as a second monitor on the new retina mac but then after a few seconds the options disappear and they go back to being separate monitors. Just wondering if anyone has been able to make this work as I'd hate to have to sell my 2009 mac. Thanks in advance.

I have successfully connected (via a minDisplayPort cable) a late-2009 iMac to a late-2014 iMac retina with no problem. The retina uses the older iMac as a second screen. As it says above Command-F2 on the old iMac switches between external and internal display.

Hello. Just came across this thread. I have a mid 2010 21" Imac. I would like to purchase a new 27" IMac retina. Can I use my old IMac as a second display ? The Apple Store told me no?

Can the 2nd monitor be 5K? I.E. the HP Z27q running at 5K resolution. This monitor requires 2 display port connections or and will definitely not look good at 4K.

I have tried to do this but it is not working. I have connected my iMac Retina (2015) to my iMac (2009) Lightning port to mini display port, I have tried command F2 on both keyboards and have tried command alt F2, command function F2, none of these seem to work. Do you have any other suggestions?

I am battling the same issue, except that my computers are late 2015 iMac Retina 5K as a main computer, and I am trying to connect late 2013 iMac. I used thunderbolt to thunderbolt connection & Command-F2 (Command-Fn-F2), but I get no sign that they are talking to each other. A note on apple website says that 2013 iMac should still have/support Target Display Mode, so technically it should be possible, but I am not sure what I'm doing wrong...

Connecting an old & small hp monitor to either iMac works, but two of them via thunderbolt cable does not do anything.

Did anyone figure this out?