As an owner of a Kensington SD 4600p USB-C Dockingstation I experience problems connecting my 4k60Hz capable TV to Intel HD515 Graphics. While the dockingstation and TV support 4k60Hz, the Intel Control Panel just gives me the 30Hz option.
SAMSUNG Galaxy Tab Pro S with Intel HD515
Kensington SD 4600p USB-C Dockingstation (4k60Hz capable)
SONY XD80 43" TV (4k60Hz capable)
What I want to achieve:
A 4k60Hz connection between the Tablet and TV by means of the dockingstation.
I can only select 30 HZin Intel Control Panel.
What I tested so far:
I tested the TV and HDMI cables with another PC (Nvidia GPU) and 4k60Hz works perfect there.
I followed Kensingtons suggestions given on their support page for the dockingstation concerning the problem, but had no success.
I tested another 4k Monitor with Diplayport, but had no success, either. It´s not recognised.
What I suspect to be the problems cause:
As the TV is 10bit and Intels driver seems to give 10bit output by default if it´s supported, I think there is not enough bandwidth left with HDMI 2.0 to support 60Hz. Chroma 4:4:4 seems to be active by default, too, and that and the 10bit colour exceeds HSMI 2.0s bandwith capabilities. When driving the TV with the Nvidia GPU I had to choose between 10bit or Chroma 4:4:4 at 60 Hz, both is only possible with Diplayport 1.2 or at 30 Hz.
Another possibility could be that Samsung only allows their tailored graphics driver on the tablet, maybe they restricted 4k to 30Hz. I wasn´t able to install Intels original driver by the method you give on your support page. It always says it´s not compatible. Is there another way to do this?
What Intel can do:
If you could confirm my assumption or give some info on that, it would be of great help to me. There are so much possibilities for such an error with USB-C and DP Alt. mode and all that stuff, but I´m trieing to sort it out between Intel, Kensington and Samsung.
Giving options in your Control Panel to choose output Colour Depth (bpc) and chroma would be of very great help, too. Such options are standard with graphics vendors except for Intel. With Displayport 1.2 you don´t have that problem, because of the slightly higher bandwidth.
Please have a look at this topic, as it affects nearly every USB-C device without descrete graphics (nearly all of them) in combination with a 10bit display over HDMI 2.0 (every HDR TV on the market). It seems to be correlated to the issues people experience with DP1.2 to HDMI2.0 adapters and your graphic solutions. (see the various threads about this).