Connect Dell P2715Q (miniDisplay Port) to Thunderbolt 3 iMac 2017

Discussion in 'iMac' started by Shevchenko, Jun 19, 2017.

  1. Shevchenko macrumors newbie

    Jun 19, 2017
    Hi, i have a new iMac 2017 and i plan to connect a second display, Dell P2715Q

    The P2715Q on my MacbookPro is connected via Display Port to Mini Display Port, but i bought the Apple Thunderbolt 3 to Thunderbolt 2 adapter but the P2715Q is not recognized by the iMac.

    Later, i read this:

    So it seems that this adapter do not work with DisplayPort or MiniDisplayPort displays.

    I'm desperate, I need to connect the P2715Q to work.

    Does anyone know of an adapter or could you explain how to connect the P2715Q to the new iMac 2017 for Thunderbolt 3?

    Many thanks
  2. shaunp macrumors 68000

    Nov 5, 2010
    These monitors do work display port to mini display port. I've used two of them on a Mac Pro that way. I read somewhere that you need the monitor to be the end device on the thunderbolt chain as it's not thunderbolt, it's display port - i.e. if you had an external TB disk and put this between the monitor and the iMac it would work, hence the bit in the link you have about not working with display port and mini display port devices. This is a TB adaptor not a DP adaptor.

    Hope that points you in the right direction.
  3. casperes1996 macrumors 68040


    Jan 26, 2014
    Horsens, Denmark

    A USB-C -> Mini Display Port cable should work. Won't double-up as a Thunderbolt cable, but for display duty it should work
  4. ccc3 macrumors newbie

    Jun 27, 2017


    Did you manage to make it work ?
    I have the same monitor and it worked flawlessly with a late 2012 27" iMac using a mini displayport/thunderbolt 2 - displayport cable (like this:

    I got a new iMac 2017 27", and bought a usb-c/thunderbolt 3 to displayport cable (like this:, and monitor screen stays black and monitor says there's no signal.

    So I went to the Apple Store and bought an adapter usb-c/thunderbolt 3 to mini displayport/thunderbolt 2, and tried to use the cable that came with the monitor, the one that I was using with the late 2012 iMac, and still nothing.

    I also tried connecting the iMac to another monitor, and still nothing.

    What the hell as Apple done ? The older iMac was running the same OS (Sierra), so I don't see how this could be a software issue.
    --- Post Merged, Jun 27, 2017 ---
    Not OP, but I tried it with such a cable and it didn't work.

    Did anybody manage to connect a new 2017 27" iMac to a Dell P2715Q ?
    If yes, please share how.
  5. dborod macrumors regular

    Jul 22, 2002
    I have read elsewhere that you need to push the cable quite firmly into the iMac for the connection to be made.
  6. ccc3 macrumors newbie

    Jun 27, 2017
    Are you trying to get me to mess up my iMac or what ?
    I know how to plugin a cable.
    My phone is charging fine from the other USB-C port.
    Every time I tried (multiple time with each usb-c cable or tb2 cable + tb3 adapter) the cable was properly pluged in. There was nowhere to push it further.
  7. dborod macrumors regular

    Jul 22, 2002
    I am neither encouraging you to mess up your iMac nor suggesting you don't know how to plug in the cable.

    I was merely trying to be helpful and relay some information that I had read elsewhere in these forums.
  8. kap28 macrumors newbie

    Jun 27, 2017
    Same issue here with my 2017 iMac 27" and Dell U2713HM (27", 2014, 2560x1440). Try pretty much EVERYTHING, nothing work. See attached image for info about what I have tried. The monitor work fine with my previous late 2012 iMac 27".

    It is very strange that they listed "Native DisplayPort output over USB‑C" on spec page but a simple USB-C to DisplayPort isn't working. I also try the same cable and display with 12" MacBook, work fine. All HDMI connections I tried seem to max out at 1080p.

    Had a few phone calls with Apple support, they said the only option is to get a new monitor or update monitor firmware (which doesn't exist).

    This is the cable that I got from eBay which doesn't work. I found this on Amazon said it support 2017 iMac/iMac Pro, not sure if this will work (I don't live in US, so can't buy it).

    Also anyone know anything about USB-C Port (with DisplayPort ALT mode)? Is it required to make this work?

    Attached Files:

  9. propower macrumors 6502a

    Jul 23, 2010
    I tried with my Dell U2715H and iMac 27 2017 - TB3 to TB2 adapter - TB2 to Display port or TB2 to miniDisplay port - nothing. The monitor works fine with my 2013 Mac Pro. Bummer....
  10. ccc3 macrumors newbie

    Jun 27, 2017
    I was (mostly) joking. Not sure how you can mess up plugging in a cable.
    --- Post Merged, Jun 28, 2017 ---
    That's almost identical to what I tried, except I didn't have the 2 cables that gave you 1080p resolution.

    Apple also told me to get a new monitor (f**k you Apple, I am not giving you 1500 euros for a monitor). The monitor is fine. When it's receiving the proper signal, it works. The issue is with the iMac not sending the proper signal.

    And I don't want to buy another monitor. I bought this one less than 1 month ago. It's too late to return it now (I think), and I don't want to sell it as a 2nd hand for half the money.

    This weekend I will take the iMac to the Apple store to see what they got to say about it.
    Will try to update.

    BTW, nice graphic explaining what you did.
    Mind if I steal it when trying to post the question on other forums ?
  11. kap28 macrumors newbie

    Jun 27, 2017
    Thanks, glad to know I'm not the only one.

    All good, go ahead.
  12. ChoPraTs macrumors newbie


    Oct 27, 2009
    Madrid, Spain
    Wow! I'm thinking about to buy a new iMac 27 2017 version, but I'm concerned because I don't know how will I be able to connect my Dell U2715H, now connected without problems to an old iMac 27 mid 2010 through Mini DisplayPort.

    I've read that the Apple Adaptor USB-C to Thunderbolt 2 is not compatible with Mini DisplayPort displays:

    I've also noticed that all of the USB-C to Mini DisplayPort adapters sold in Amazon specify: "not compatible with MacBook Pro 2017 and iMac 2017", like this:

    Apple also sells an USB-C to HDMI adaptor (, but I'm not sure I can get the full resolution (2560x1440) of the Dell U2715H thought HDMI, I think it can only handle 1080p.

    Seems that doesn't exist any possibility to connect a Mini DisplayPort display to a new iMac 2017 and get the max resolution, right?
  13. ccc3 macrumors newbie

    Jun 27, 2017
    You will only manage to get 1080p.

    For the moment there seems to be no solution to connect such monitors and get a 4k resolution.
    Maybe call Apple and let them know that they are losing sales because of this. I probably wouldn't have bought my new iMac if I would have known.
  14. ChoPraTs macrumors newbie


    Oct 27, 2009
    Madrid, Spain
    In this other post, seems that someone could connect the monitor to the new iMac 2017 through a Thunderbolt HDD:

    Should it work if I buy, for example, an OWC Thunderbay 4 and connect my Dell U2715H to this enclosure, and the enclosure to the new iMac with the USB-C to Thunderbolt 2 adapter?
  15. CWallace macrumors 603


    Aug 17, 2007
    Seattle, WA
    At least a few people on this forum have reported they cannot connect an external monitor to their iMac via USB-C until they went back and checked the cable and noted it was not fully seated. As soon as they ensured it was, (it evidently has a detent or something you have to push past), it worked.
  16. user1234 macrumors 6502


    Mar 3, 2009
    This cable is said in other threads to work and they themselves list it as compatible with the 2017 iMac:

    I hope it works because I'm planning on getting it to use with my Dell P2416D.
  17. Glockworkorange macrumors 65816


    Feb 10, 2015
    Chicago, Illinois
    This plug works fine on my Dell P2715Q when using the TB3 port on my 2016 13 inch MBP. There is an HDMI option, but for whatever reason, HDMI doesn't look nearly as good as when you use DP.

    Lot of angst over this issue on the forums. The plug really is top notch and works well. Have had zero issues.
  18. kap28 macrumors newbie

    Jun 27, 2017
  19. macsplusmacs macrumors 6502

    Nov 23, 2014
    Hello everyone.

    I just got my i7 580 2017 iMac and I have an external DELL P2715Q Display working fine!

    This is the cable I am using:

    So far so good. About the only thing I have not done is a reboot. still getting my iMac up to speed downloading apps.

    I bought two cables because I hope to bring my other Dell 4K monitor over and hook up both at the same time.

  20. Weerik macrumors newbie

    Jul 18, 2017
    Hi guys,

    Since i received my iMac last week i've discovered the same problem of course. I try to hook up my external monitor (Dell P2715Q) to my iMac 5K 2017, without succes.

    Since Masplusmacs made the last reply with a possible solution, i am pretty curious if this is the working solution to this problem.

    I hope to hear from you guys!
  21. Nlfyskiod macrumors newbie

    Jul 11, 2017
    Apple is not the original display is to use the converter, Apple's product design must be different, some monitors, you look at the above to have a converter ..........
  22. theluggage macrumors 68040

    Jul 29, 2011
    Just to knock that specific issue on the head: the Apple store page on the TB2/TB3 converter clearly says "This adapter does not support DisplayPort displays like the Apple LED Cinema Display or third-party DisplayPort and Mini DisplayPort displays." The same is true of 3rd party TB2-TB3 adapters (e.g. StarTech) and Intel's reference TB2/TB3 adaper design.

    Thunderbolt has two ways of transmitting DisplayPort: (a) by encoding the DP data as part of the TB data stream or (b) detecting when a displayPort device/cable is plugged in and switching the port to "displayPort" mode.

    (a) relies on a thunderbolt display, hub, or other peripheral at the other end to extract the DP data from the TB signal, while (b) works differently on TB2 ("displayPort legacy mode") than it does on TB3 (USB-C DisplayPort Alternative Mode).

    The TB2-TB3 connector only supports method (a) of connecting a display: you'd need a Thunderbolt display, a TB2 hub (with display output) or a TB2 hard drive etc. with a "full featured" TB2 daisychain port.

    I guess the theory was that you would use a far simpler, cheaper TB3-to-DisplayPort adapter cable if you wanted to achieve (b) - although it would have been kinda useful...

    ...if TB3 to DisplayPort cables/adapters aren't working, then that's more worrying and, yeah, Apple shouldn't be falling back on the "blame the display" line.

    I've got an iMac on order, as well as the Plugable cable mentioned above, and have a Dell S2817Q 4k display. Should be here in the next day or so - I'll post whether or not it works...
  23. Olganech macrumors regular

    Mar 21, 2015
    With Dell monitors I have found that you have to have a single cable. They do not work or do not work well if you have a cable connected to a dongle.
  24. Mark Holmes macrumors member

    Mark Holmes

    Sep 22, 2010
    San Diego CA
    Yep. I'm using this cable on my Dell 2715h with my 2017 i5 580 8gb w no problems.

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