[FIXED] Trouble getting 1440p@120hz/4k@60hz to work with 7970ghz + LG OLED B9

BigBallerB · March 31, 2020

System Configuration:

Motherboard: ASROCK pro B75 PRO3
CPU: Intel i5 3570
Memory: 8GB GDDR3
GPU: GIGABYTE WINDFORCE 7970 GHz
VBIOS: xxx-xxx-xxx (actually shows this)
Driver: 20.3.1
OS: Windows 10 x64 (18363.720)

To my knowledge my GPU has these output options: 2x Mini DisplayPort (v1.2), 1x HMDI (1.4) and DVI. As the title says I'm trying to get 1440p @120hz mainly, the 4k should theoretically also work since the bandwidth usage is similar.

My TV does not have a DisplayPort input. It does have 4x HDMI (2.1, or at least 2.0). After having done some research I've decided to use a Mini DP to HMDI active converter and HDMI cable to hook up my PC to the TV.

However, I have not been able to get it to work. Simply plug and play does not allow me to go over 30hz on either resolutions. I then tried to create a custom resolution through the AMD driver settings, but no luck there either. I've seen some websites advising to change the pixel formation from RGB to YCbBCr 4:2:2. However, the AMD software shows no option to alter the pixel formation. However, when I use my HDMI 2.0 cable YCbBCr show up however.

I realize my hardware might be a bit old to produce this output/ However, since my mini DisplayPort is v1.2 (I think?), it should be able to ouput 1440p @120hz. The converter should be able to handle the conversion (rated HBR2, enough bandwidth for 1440p@120hz), and HMDI 2.0 should be able to handle it as well.

I'm at wits' end, any and all help is appreciated. Thanks!

FIXED EDIT:

After spending more time than I care to admit, I found the solution. May it help someone else some day.

BiggieBagelz · April 3, 2022

Hey can you give some more information on this issue that you had... I'm trying to figure out if I'm having a similar issue. I'm trying to run an ultrawide 3440 x 1440 on a PopOS machine running 2 Radeon 7970GHz cards in crossfire. I cannot get my ultrawide to display the full 1440p, but I can get it to run at 1080p at the same 21:9 aspect ratio.