PC Graphics

[Dorstlesser]

Dear all,

I have hooked up my RX 5700 to an LG OLED C9 and I'm trying to enable 10 bit color at 1440p120 with HDR enabled in Windows 10 settings. I'm on the newest driver version and Windows version and currently the only option I have for color depth and pixel format is 8-bit 4:4:4 RGB (full and limited range). The options for 10- or 12- bit, YcBcr and chroma subsampling are not showing. Changing refresh rate to 60 Hz does not change this.

In the past (older driver versions) I did have some of these options available and I'm having a hard time figuring out what is now causing this limitation. Is it a specific combination of refresh rate, VRR, HDR, resolution that is causing these restrictions?

From listed specs for RX 5700 cards it seems 4K60 @ 30 bpp should be supported. 1440p120 requires less bandwidth than 4k60, so this suggests that in principle the RX 5700 should be able to output 1440p120 @ 30 bpp.

Anybody have any insight?

[Matt_AMD]

Sounds like a bandwidth issue. Radeon Software will only display the maximum supported pixel format/colour depth options, based on the display connection currently used (eg, DP/HDMI), the current resolution and refresh rate used, and information pulled from the displays EDID. 

The RX 5700 has a HDMI 2.0 port which has less bandwidth available than the DP1.4 ports, which can run 4K120HZ with HDR.

4K60 is supported via HDMI, but I believe it might be using a 4:2:2 or 4:2:0 rather than 4:4:4.

If you disable HDR, do you get any options for 10 bit colour, with the refresh rate at either 120/60hz in Radeon Software.