Question Monitor Colours Wrong With Displayport But Fine With HDMI

Sep 23, 2021
I recently bought an Iiyama GB3461WQSU 3440x1440p 144Hz monitor and I had used it for a few months with my MSI GTX 1080 card with no issues and it could manage 144Hz using the included DisplayPort cable. A couple of months ago I noticed the colours were 'off' and the whites were more grey, I had a second monitor plugged in using HDMI and the colours on that were unchanged. I tried unplugging the DP cable and re-plugging it but this would first make the entire screen have a strong green tint, I re-plugged the cable again and next time it would have a pink tint, and third time re-plugging it the colours would be slightly grey again but never 'correct' like they used to be. My GPU has 3 DP ports and the monitor has 2, so I tried the cable in all the different port combinations which made no difference. I bought another DP 1.4 cable and that had the exact same symptoms. The monitor displays the right colours only while using an HDMI cable but this only allows me to use 100Hz at 3440x1440p which is very frustrating as this monitor cost me £350. I've updated the GPU drivers which didn't make a difference.

Has anyone got any suggestions, please? Thanks in advance
try outputting to a different display through DisplayPort to see if it is possibly the GPU having issues.
and vice versa;
also try the display on another system which is outputting through DisplayPort to absolutely verify if it is the display itself.