R9 280x DisplayPort problem

[hin]

I have a 10.13 build. Now I am upgrading the build by adding a graphics card R9 280x , every thing works fine, except the graphics card DisplayPort. It unable to output any signal, but ones I Connected graphic card HDMI to a Monitor it both works fine. If I disconnect the HDMI, the DisplayPort Lose the signal. My setup only allows one 4K monitor.

 

[BreBo]

@hin, please update your profile (account details) with your Motherboard, CPU and iGPU or Graphics Card(s).
If you have a prebuilt computer enter make and model instead of motherboard.

Profiles are mandatory so that others can assist you.

 

[hin]

Thanks for help. Somehow looks like I have fixed the problem I have mansion, but it cost a new problem which only able output 3840x2160 at 30Hz , and seems like don’t have any graphics acceleration.

Here is my specification of my build

Mac OS 10.13.6
i5 8500
gigabyte H370N WiFi
Sapphire R9 280x 3GB
Bluetooth dongle


Note
I don’t use the onboard WIFi

 

[BreBo]

Here is my specification of my build

Mac OS 10.13.6
i5 8500
gigabyte H370N WiFi
Sapphire R9 280x 3GB
Bluetooth dongle

Great, now please update your profile (account details) with them.