I cannot get my monitors native resolution over HDMI

[lordsnake]

I have a PC with an ATI Radeon 4600 and an LG ultrawide monitor.
For some reason I cannot get the full resolution 2560 x 1080 over HDMI, I have to use VGA or DVI. I realise it doesn't make any difference to picture quality, but DVI and VGA do support sound.

It isn't the monitor, as I works fine on another PC.
It isn't the HDMI cable.
So presumably it must be the gfx card. But why would it only not support this resolution via HDMI ?

 

[maxalge]

I have a PC with an ATI Radeon 4600 and an LG ultrawide monitor.
For some reason I cannot get the full resolution 2560 x 1080 over HDMI, I have to use VGA or DVI. I realise it doesn't make any difference to picture quality, but DVI and VGA do support sound.

It isn't the monitor, as I works fine on another PC.
It isn't the HDMI cable.
So presumably it must be the gfx card. But why would it only not support this resolution via HDMI ?

older cards max out at 1080p over hdmi

to get higher resolution you need to use DVI as you have found out

 

[Glenwing]

Maximum resolution of HDMI 1.2 is 1920×1200 at 60 Hz.

Radeon 4000 series supports a few HDMI 1.3 features but is still limited to the bandwidth of HDMI 1.2.