Graphics card cannot output max resolution

[tsun hei]

I have a Dell U2515H 1440p monitor
When i connect the hdmi cable to my motherbard(intel hd graphics 630)
I can set my monitor to max resolution(2560x1440)
But when i connect the monitor to the graphics card(sapphire rx 580), the max resolution i can select is 1366x768
I have tried installing the driver again and try the two hdmi ports, it still doesn't work.
As the hdmi port is hdmi2.0
I don't think that is the port's problem
The cable supports hdmi2.0, so as the monitor
What's wrong with my graphics card then?
By the way, when i try to play playerunkown's battleground on my graphics card, it said that dx11 features are required to run game, what does that mean?Everything was fine when i run on intel hd graphics 630

 

[Lutfij]

It reads to me like you performed a GPU upgrade. If so then dd you use DDU to uninstall your previous drivers? Later on using the latest drivers found off AMD's support site? Prior to this point, you're sure your motherboard BIOS is up to date?

 

[tsun hei]

It reads to me like you performed a GPU upgrade. If so then dd you use DDU to uninstall your previous drivers? Later on using the latest drivers found off AMD's support site? Prior to this point, you're sure your motherboard BIOS is up to date?

I didn't performed a gpu upgrade, this was my first PC build
Everything was new, even the monitor and the cables