R9 280X to drive two P2715Q 4k monitors?

Discussion in 'Mac Pro' started by AndreeOnline, Jan 9, 2015.

  1. AndreeOnline macrumors 6502

    AndreeOnline

    Joined:
    Aug 15, 2014
    Location:
    Zürich
    #1
    Has anyone tried to drive two 4k screens with a 280X?

    I have a 5.1 with a non-flashed MSI R9 280X 3GB. It has two MiniDisplay ports.

    The Dell P2715Q is a $699 UHD monitor that checks these boxes:

    • 60Hz
    • IPS technology
    • SST panel
    • 99% sRGB and around 75% Adobe

    I'd probably default to a higher end monitor, but the price/performance ratio seems good here. And most reviews are positive. Nice way to save some money with a two monitor setup.
     
  2. AndreeOnline thread starter macrumors 6502

    AndreeOnline

    Joined:
    Aug 15, 2014
    Location:
    Zürich
    #2
    Is anyone using the R9 280X to drive ONE of these new monitors?

    If so, it would be great to hear if it works.
     
  3. ilikewhey macrumors 6502

    Joined:
    May 14, 2014
  4. Mic-M4c macrumors newbie

    Joined:
    Jan 9, 2015
    Location:
    Paris, FRANCE
    #4
  5. Mic-M4c macrumors newbie

    Joined:
    Jan 9, 2015
    Location:
    Paris, FRANCE
    #5
    Hi. Can you post a screen shot of your System preferences > Monitors to see if you are in 4K@60Hz, please ?
     
  6. kennyman, Mar 15, 2015
    Last edited: Mar 18, 2015

    kennyman macrumors regular

    Joined:
    May 4, 2011
    #6
    I have just pulled the trigger and bought a Dell P2415Q for $585. Now I also have a 280X flashed. Could you please confirm whether the Dell is compatible with the 280X @60 Hz. Any artifacts or image/window tearing?
     
  7. MacMutsch macrumors newbie

    Joined:
    Sep 19, 2014
    #7
    I’m currently using a Dell UP3214Q (UHD/3840x2160) and a LG 31MU97 (4K/4096x2160) with my (flashed) GigaByte R9 280X.
    Although OS X 10.10.3 provides better graphics drivers I still have to use SwitchResX or Display Menu to get all the useful HiDPI Resolutions – with System Preferences I can only select the native UHD/4K resolution but none of the HiDPI.

    Attached a screesnhot of the most useful resolutions I can use with my LG 31MU97 (before 10.10.3 only 50 Hz were possible with this 4K Display), I could also use the corresponding UHD resolutions @ 60 Hz with the Dell UP3214Q.

    I haven’t figured out yet if I can use both UHD/4K displays @ 60 Hz at the same time with the two (mini)display ports of my single 280X – I haven’t tested this configuration in detail but up to now I only get black screens (which is why one of those displays is currently connected to HDMI, which gives you only 30 Hz of course.
    No problem at all with my nMP / D500 though, with the nMP and 10.10.3 all useful HiDPI resolutions can be seleceted with the OS X System Preferences).

    I’m curious what you have to report with your Monitors, R9 280X and OS X versions ;O)
     

    Attached Files:

  8. kennyman, Mar 16, 2015
    Last edited: Mar 18, 2015

    kennyman macrumors regular

    Joined:
    May 4, 2011
    #8
    Thanks, mine is a Dell P2415Q. From some reports online, looks like it will work at @30 Hz...I will give it a try and return it if is does not work at 60 Hz. Is there any settings on the Dell monitor itself to select SST or MST mode?
     
  9. MacMutsch macrumors newbie

    Joined:
    Sep 19, 2014
    #9
    I’m sorry that I can’t provide first hand experience with the P2715Q but with my UP3214Q (as well as the LG 31MU97) I just had to enable „Display Port 1.2“
    (OSD -> Menu -> Display Settings -> Display Port 1.2) in order to get the full 60 Hz.

    I wish you success!
     
  10. kennyman, Mar 18, 2015
    Last edited: Mar 18, 2015

    kennyman macrumors regular

    Joined:
    May 4, 2011
    #10
    Thanks, I have received my monitor, it is P2415Q (not the 27 inch). Unboxed and connected it to 280X, mDP to DP on the monitor. First impression, looks gorgeous and solid, booting went fine, but resolution went crazy with some retina resolution. I am still at 30Hz. I did not have enough time to play around with it. However, I cannot see the settings you mentioned. My menu has no display port, any idea? I am on Yosemite 10.10.2

    UPDATE: Ok, I downloaded SwitchResX and I can set 60Hz now, thanks, all good.
     

    Attached Files:

  11. kennyman macrumors regular

    Joined:
    May 4, 2011
    #11
    Dell P2415Q works fine with 280X @60Hz with mDP. After messing around with SwitchResX, I have decided to permanently mod my pref file for retina mode (only Apple retina mode works right now) and have done some resolution adjustment following this

    I need some more time to play around, to delete and add some custom resolutions, so far, looks insanely insane...:)
     

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