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Anyone else using a 4K TV as a monitor?

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Joined
Jan 4, 2011
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616
Motherboard
Asus Z170 Hero VIII
CPU
i7-6700K OC @4.6GHz
Graphics
RX 580
Mac
  1. iMac
Evening! I'm using a Sony Bravia as my main monitor.

Working (HDMI to DVI cable)
  • 1080p HiDPI (retina) via SwitchResX
  • Chroma 4:4:4
  • 60Hz
Not working (Direct HDMI cable)
  • 60Hz via HDMI 2.0
  • No text scaling options in Display settings (Mac thinks the TV is 1080p and not 4K)

1) Is there a way to force the Mac to see the TV as a 4K monitor?

2) I get the odd problem with this TV (a strange refresh/lag bug) which can be fixed by switching the TV input away/back to the Mac. Sometimes the TV doesn't register the Mac waking from sleep or screensaver too, I have to reconnect it (rare).

Anyone else having similar issues, or over come them?

Interested in how any people are using 4K TV's as monitors too. Small bugs aside, it makes for a great experience!

Update

Using a DP 1.2 to HDMI 2.0 cable fixed the refresh and wake issues, everything working as it should.

EVGA 980 Ti SC+ -> Club DP 1.2 to HDMI 2.0 -> Sony Bravia X85C, 65".

Update 2

Stil have the refresh bug (gah!). But it's a more stable connection.

Update 3

Getting a blank blue screen after turning the monitor on after the machine has been left (while running - not sleeping). Back to the DVI to HDMI cable!
 
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OS X doesn't support HDMI 2.0. If you're lucky, the Pixel Clock Patch will increase the bandwidith to allow for 4K@60Hz.

This doesn't seem to work for most people, so 4K@60Hz through HDMI is no option. Most likely you'll have to use an active DP 1.2 to HDMI 2.0 adapter. They're still quite rare (and more expensive than HDMI 1.4 adapters), but they do the trick for most people.
 
OS X doesn't support HDMI 2.0. If you're lucky, the Pixel Clock Patch will increase the bandwidith to allow for 4K@60Hz.

This doesn't seem to work for most people, so 4K@60Hz through HDMI is no option. Most likely you'll have to use an active DP 1.2 to HDMI 2.0 adapter. They're still quite rare (and more expensive than HDMI 1.4 adapters), but they do the trick for most people.

Thanks Fl0rian. I had spotted that patch before, but since 60Hz UHD over DVI was working, I thought it was best left alone. Do you know if the patch would affect normal DVI connections/resolutions?

As my card is Maxwell, I may try the IOKit patch now it's been updated to 10.11.5.
 
IOKit patch didn't help - can't get 60Hz over HDMI still.

I'll stick with the DVI (Mac) to HDMI (TV) cable. Unless I can find a DP1.2 to HDMI 2.0 converter, of course :¬)

Edit: found and ordered (an expensive) DP1.2 to HDMI 2 converter. I hope it fixes the DVI to HDMI refresh bug!
 
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4K@60Hz shouldn't work over DVI actually. The bandwidth of DualLink-DVI is the same as HDMI 1.4, so you should be limited to 4K@30Hz (or 1440p@60Hz).

I think the Pixel Clock Patch "unlocks" all ports. Usually it's just the HDMI port which is somehow limited though.
 
4K@60Hz shouldn't work over DVI actually. The bandwidth of DualLink-DVI is the same as HDMI 1.4, so you should be limited to 4K@30Hz (or 1440p@60Hz).

I think the Pixel Clock Patch "unlocks" all ports. Usually it's just the HDMI port which is somehow limited though.

Thanks for the clarification.

It works, been using it for weeks. I'd read of a few people who were using a specific DVI to HDMI cable to get it 4K 60Hz Chroma 4:4:4 working. I can tell the difference between 30 and 60 Hz too - years of gaming as a kid!

(Also confirmed via SwitchResX.)
 
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It's a quite lucky combination of GPU, cable and display, I guess.

I have seen a similar "lucky combination" myself: R9 280X, passive DP->HDMI (maximum is 1080p) & my Dell U2515H gives 1440p@60hz, although it shouldn't.

But you can also have bad luck: Can't find any DVI->HDMI adapter which allows my GTX 770 to drive the exact same screen at 1440p, although both the adapter and the DVI port are spec'ed as "Dual Link". Display just passes out with "incompatible input timing".
Same combination works perfectly fine on my GTX 780 though... :D
 
It's a quite lucky combination of GPU, cable and display, I guess.

I have seen a similar "lucky combination" myself: R9 280X, passive DP->HDMI (maximum is 1080p) & my Dell U2515H gives 1440p@60hz, although it shouldn't.

But you can also have bad luck: Can't find any DVI->HDMI adapter which allows my GTX 770 to drive the exact same screen at 1440p, although both the adapter and the DVI port are spec'ed as "Dual Link". Display just passes out with "incompatible input timing".
Same combination works perfectly fine on my GTX 780 though... :D

It's a game of luck it seems, especially so when using a TV! :¬)
 
HI! I'm using a Gigabyte GTX970 throught HMDI 2.0 and with HDMI 2.0 cable connect in a Philips TV 4k 6300 series, @60mhz, no problem to connect in any time. Just plug the cable and voilà!
 
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