4k, 60hz HDMI issue

[FredrikMa]

Hi. I work in a big company with thousands of computers. Our main laptop model at the moment is the ProBook 640 G8. Our users are struggeling to get image on screens in conference rooms, where the screens support 4k, 60 hz resolution. They connect the computer to the sceen with HDMI and the computer negotiate 4k, 60hz with the screens. The computer cant display that over HDMI though because the HDMI-port är version 1.4b, so they just get a black screen. Why does the computer negotiate 4k, 60hz, when it cant be displayed over HDMI? Is there a solution  to this problem? Our users dont know whats happening, they just think the computer is malfunctioning.

[banhien]

@FredrikMa 

It has  HDMI v1.4b supporting: up to 4096 × 2160 @ 30 Hz with HDCP 2.3. With a right HDMI cable, you should be able to get 4096 × 2160 @ 30 Hz. As you know: resolution goes up, refresh rates will go down and vice versa. Machine would negotiate with the monitor and try to get a good match. You can use 1920 x 1080 and ask monitor to scan up to cover full screen.

Hope this helps

I can watch FHD movies on my 4K TV all the times

Regards.

[FredrikMa]

Thanks for your reply. The problem though is not the we really need a high resolution and refresh rate. The problem is the the computer negotiate 4k, 60hz with the screens over HDMI, resulting in no picture at all since HDMI 1.4b cant display that. Our users does not know they manually need to lower resolution/refresh rate the get the screen displayed. They make a support ticket to our helpdesk. Why does not the computer and screen negotiate 4k, 30hz instead which could be displayed over HDMI 1.4b? Or 1920x1080 60hz?

[FredrikMa]

The screens are Promethean screens. Could the problem be with the screens and not with the computers?