Hello GoodKitty,
Vizio P series Tv is alreay a ‘chanllange”, Nvidia 600 series on itself is also quite a challange and i have not yet come across a 5 meter/20 feet cable without it being active that would actually be bale to output 18gbps, challange nr 3 so to say.
Often the Strange colors mean there is not enough bandwidth available and related to either HDMI Cable and or settings of the source/pc. The last one you can check, by setting the color depth to 8Bit and  Chroma to 4:2:0 or 4:2:2 if the software lets you …