I have asus r9 280x and have artifavts issues, many r9 280x users of all brands have this issua. Mine is small, i rarelly get artifacts. Some people say its vram overheating, other say is bios, other say is drivers, other say amd is crap xD
But u cant go wrong with any, u can have unluck and get Artifacts, or u can get no artifacts
The card is amazing, i recommend it! 4 monitors is a little bit, and r9 280x 6gb isnt worth it, as its memory bandwith aint enough for 6gb. Get away from msi, loud fan, toxic is the fastest but hottest and consumes more power, the asus is the quietest and cooler, gigabyte is also good.