Only 30hz refresh rate - Sierra 10.12.5 - nVidia GTX 750TI - 4K Panasonic TV

[the_gael]

In Mac OS I only get 30hz when screen is driven at 3840x2160.
I have a triple boot system with Mac OS / Windows 10 / Elementary OS

When I boot into Windows 10 my refresh rate is 60hz when resolution is set to 3840x2160.

I would like to achieve 60hz in Mac OS as well.

I suspect this must be a software limitation in Mac OS as everything is known to be working on the hardware side due to its performance in Windows 10.

Could the Pixel Patcher resolve this issue or is there another solution?

 

[Frugoss]

Is it connected to hdmi?

 

[the_gael]

Yes, HDMI 2.0 cable from my GTX 750Ti.
I am aware now after a lot of googling that there is a software limitation of MacOS using HDMI. Unfortunately my TV does not have DP and having just bought it I don't want to buy another one.

I was wondering if there are any solutions to get round the software limitation.

 

[Frugoss]

Yes, HDMI 2.0 cable from my GTX 750Ti.
I am aware now after a lot of googling that there is a software limitation of MacOS using HDMI. Unfortunately my TV does not have DP and having just bought it I don't want to buy another one.

I was wondering if there are any solutions to get round the software limitation.

Unfortunately not for now. Maybe Apple will announce something on June. Keep fingers crossed!

 

[slim.jim]

You could try the Pixel Clock Patch V2. It does mention enabling HDMI 2.0 on Maxwell GPUs but I believe it says it is untested.

Other option is to get an active DP 1.2 to HDMI 2.0 adapter.

 

[the_gael]

You could try the Pixel Clock Patch V2. It does mention enabling HDMI 2.0 on Maxwell GPUs but I believe it says it is untested.

Other option is to get an active DP 1.2 to HDMI 2.0 adapter.

slim.jim - OK I may look at that, I would have to buy a Graphics card with a DP output as well as currently I don't have one of these. I think I have seen posts about issues with DP adapters where boot screen is not displayed - is there anything I should avoid?

 

[TomHsiung]

Hi, @the_gael

How about your 4k @60 at present?

 

[the_gael]

Hello @TomHsiung yes, I have 4k@60Hz on my Hac which is connected via an Active DisplayPort to HDMI adapter (this is because I have no DisplayPort on my 4k Panasonic TV.

Incidentally if I select scaled in Displays preference pane I will only get 30hz.

I have also noticed on my Main Hac which has a Samsung 4k Monitor and is connected by DisplayPort I have 4k@60hz but if I were to select Default for Display on that one it will drop to 1080p as the macOS does not recognise its native resolution.

What I am saying is that there might also be a requirement for the OS to recognise that your display has a native resolution of 4K (3860x2160 in my case). My Panasonic TV is recognised by default as 3860x2160 by the macOS, while the Samsung 4k Monitor on my main has is not recognised by macOS as being a 4k native display.