MacPro5,1 + GTX680 + 4K = 60hz?

TomTomTuning

macrumors regular
Original poster
Oct 21, 2010
180
14
Central PA
Hey Folks,

I was curious if there was a way to run 60hz on this setup. I just got a Korean AMH 40" 4k display, but cant seem to run it any higher then 24hz. I'm also not sure why it running in "low resolution".

Any assistance or suggestions is greatly appreciated! :)

Specs:
2010 MacPro5,1
3.4Ghz Hexa CPU
24GB 1333Mhz Tri-Channel RAM
EVGA GTX 680 4GB FTW GPU (Flashed with Mac firmware)
1TB Samsung 840 EVO HD

NIVIDIA Web Driver 346.03.10f02
CUDA Driver: 7.5.29


[doublepost=1466440247][/doublepost]By the way, it appears to do 1080p, regular resolution, 60hz just fine.

Hopefully there's away to get 4k to work at those settings.

 
Last edited:

Fl0r!an

macrumors 6502a
Aug 14, 2007
906
526
Are you connecting via DP? HDMI is 1.4 spec, so it's bandwidth isn't sufficient for 4K@60.
 

TomTomTuning

macrumors regular
Original poster
Oct 21, 2010
180
14
Central PA
Are you connecting via DP? HDMI is 1.4 spec, so it's bandwidth isn't sufficient for 4K@60.
Via display port?
Yes, via DP. Using the cable they supplied with the monitor.
I do not have another cable to try sadly, but I can order one if suspected to be an issue.

The monitor has HDMI 2.0 and DisplayPort 1.2.
I believe the GTX 680 supports DP 1.2, right?
 

rabidz7

macrumors 65816
Jun 24, 2012
1,203
2
Ohio
Try using the C.R.U (Custom Resolutional Utility) on winDowes and if you use OS/x, use SwitchResX.
 

TomTomTuning

macrumors regular
Original poster
Oct 21, 2010
180
14
Central PA
Try using the C.R.U (Custom Resolutional Utility) on winDowes and if you use OS/x, use SwitchResX.
Any suggestions on what settings to try in the Custom Resolutions tab?
I'm playing around now with this applications, but not entirely sure what settings to use, and how to apply them.

I have to double check if 60hz is supported via the HDMI 2 ports on this monitor. I know the new reviews I watched, mentioned using the DP.
 

ActionableMango

macrumors G3
Sep 21, 2010
9,513
6,772
TomTom, if you see the link in my post #8, then this is possibly a known problem with your particular setup. You can test for it easily by booting up with the monitor off.
 

TomTomTuning

macrumors regular
Original poster
Oct 21, 2010
180
14
Central PA
TomTom, if you see the link in my post #8, then this is possibly a known problem with your particular setup. You can test for it easily by booting up with the monitor off.
I was playing around with SwithcResX earlier and needed a second monitor to boot into recovery, so I have a second monitor connected via HDMI. I rebooted with the 4K monitor turned off, once logged in I turned it back on but stilll have the sam display settings. :(
 

ActionableMango

macrumors G3
Sep 21, 2010
9,513
6,772
I was playing around with SwithcResX earlier and needed a second monitor to boot into recovery, so I have a second monitor connected via HDMI. I rebooted with the 4K monitor turned off, once logged in I turned it back on but stilll have the sam display settings. :(
The second screen may have affected the test. I would disconnect it for now and try booting up with the 4k monitor off again just to see what happens.

I realize that's not how you would want to run, but it's just a test to add data to the troubleshooting effort.
 

TomTomTuning

macrumors regular
Original poster
Oct 21, 2010
180
14
Central PA
The second screen may have affected the test. I would disconnect it for now and try booting up with the 4k monitor off again just to see what happens.

I realize that's not how you would want to run, but it's just a test to add data to the troubleshooting effort.
First off, I really appreciate you helping out!

I tried it again with the 2nd monitor completely disconnected. I even went as far as unplugging the power to the 4k monitor, then plugging it in once I knew the system was booted. However, still have the same options.

I did try the pixel clock patch, so I'm not sure if thats interfering now (doubt it).
https://github.com/Floris497/mac-pixel-clock-patch-V2

I may just purchase a newer GPU that is known to support 4k@60Hz and sell this one.
or maybe it's time for a MacPro6,1 :)

Until then I will continue to research and see if I find any other possible solutions.
 

TomTomTuning

macrumors regular
Original poster
Oct 21, 2010
180
14
Central PA
Found out that 3840x2160 is the native resolution of this monitor.
I also tried HDMI, which allows me to use 30Hz (3840x2160)

I ordered a few cables to try, since most of mine are older.
MacVidCards asked about SST and MST but I cannot find that info online.
If I cant get 60Hz, I may order a new GPU and see if that helps.
 

nigelbb

macrumors 65816
Dec 22, 2012
1,031
201
In my Mac Pro 3,1 am using a flashed GTX680 with a Philips BDM4065UC 40" 4K monitor which also has a native resolution of 3840x2160. I can use 4K@60Hz with a couple of caveats. The system hangs early in boot if the monitor is set for DP 1.2 (necessary for 60Hz). If I boot with a second monitor connected to DVI or HDMI I get the boot screen on that monitor & the Philips works OK 4K@60Hz after boot is completed. I can also boot with just the 4K monitor by connecting via HDMI then after booting unplugging the cable & connecting via DP then adjusting resolution/frequency in System Preferences->Displays.
 

Squuiid

macrumors 68000
Oct 31, 2006
1,578
889
If I boot with a second monitor connected to DVI or HDMI I get the boot screen on that monitor & the Philips works OK 4K@60Hz after boot is completed. I can also boot with just the 4K monitor by connecting via HDMI then after booting unplugging the cable & connecting via DP then adjusting resolution/frequency in System Preferences->Displays.
Thanks for this nigelbb. I have a couple of questions regarding your answers.

1. If you boot using DP cable with 4K display and DVI connected to a second monitor can you set the 4k display to be the primary display and have the settings stick or do you need to adjust this on every boot?

2. If you connect both HDMI and DP solely to your 4K display, and then use source selection on the monitor to select DP after boot, do you even need to remove the HDMI cable? Does this work? I'd like to avoid unplugging cables after a reboot, but changing source by using a monitor button is not so bothersome.

Thanks.
 

omvs

macrumors 6502
May 15, 2011
481
11
Does the monitor have an option for Displayport 1.1 vs 1.2? My SM40UNP came defaulted to 1.1, which restricted me to 30Hz and took me a few minutes to find the setting in the OSD.
 

nigelbb

macrumors 65816
Dec 22, 2012
1,031
201
Thanks for this nigelbb. I have a couple of questions regarding your answers.

1. If you boot using DP cable with 4K display and DVI connected to a second monitor can you set the 4k display to be the primary display and have the settings stick or do you need to adjust this on every boot?

2. If you connect both HDMI and DP solely to your 4K display, and then use source selection on the monitor to select DP after boot, do you even need to remove the HDMI cable? Does this work? I'd like to avoid unplugging cables after a reboot, but changing source by using a monitor button is not so bothersome.

Thanks.
1) Yes, if by primary display you mean the one that has the Dock. You can place it on either display. You can also unplug the DVI display once booted & still have the 4K@60Hz

2) Sorta kinda...Yes you can boot with both HDMI & DP connected but OS X still sees two monitors attached so even if you use source selection on the monitor it still knows that there is another monitor connected so it's not until the HDMI cable is unplugged that it sees just the one monitor. You could lose windows over on this other hidden screen.

If you don't want to plug/unplug cables or have a second monitor then you just need to be a bit disciplined & set the monitor to DP 1.1 i.e. 4K@30Hz before shut down or reboot. You can then select 4K@60Hz DP 1.2 after booting & then select 60Hz in System Preferences->Display

The issue is that the even the genuine Mac Edition GTX680 card cannot use 4K@60Hz on DP 1.2 for the Apple boot screen & on my Philips BDM4065UC 40" 4K monitor it will not even boot if 4K@60p on DP 1.2 is the only connection (I don't believe that this is true of all monitors & possibly not all GTX680s.

I reboot relatively infrequently & in any case have a choice of monitors to connect via DVI if necessary so it's really not worthwhile for me to pay hundreds of dollars for a MVC flashed card that will give me an Apple boot screen on 4K@60Hz DP 1.2
 
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mrhali

macrumors newbie
Dec 11, 2014
24
6
Just curious if you ever got this to work as I have the same setup and was thinking of new monitors.
 
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