Solution from dell that worked below.   Cause:   The computer graphics drop the color bits/depth or the refresh rate to maintain the native resolution. Ideally, the Type-C port on the computer supports DisplayPort 1.4(HBR3) or better to have sufficient bandwidth for two lanes.   Resolution:    You can configure the monitor settings to support the best image. Change the High Date speed to High Resolution:  
Seen that is a problem for others, dating back almost 4 years where the Intel 630 HD GPU displays 6 bit colour depth, not 8 bit. The only way it will display 8 bit colour depth is by disabling/uninstalling it through device manager and this is through the basic Microsoft Display Adapter Driver. Which isn't really a solution. [IMAGE] But this is what i get with the Intel Drivers enabled. [IMAGE] I have tried drivers from 2017 as these are stated as working but they give the same 6 bit depth. Trying every older driver is just not possible and i my patience is running low right now. Going from numerous online searches i'm not even sure Intel bothered to fix this issue.
7720 6 bit colour depth intel 630 hd