I bought an MSI R9 280x 3G from Overclockers UK a month ago, after installing the card it gave me artifacting and random crashes while playing games such as Guild Wars 2, League of Legends, and Hitman: Absolution. I sent it for an RMA to Overclockers and they said: "no fault found, perfomed fine on benchmark/stress tests for 24 hours", they gave me advice such as reinstalling windows and downloading the latest directx runtime from Microsoft. So I got the card back and yeah... I was still receiving artifacts while playing Guild Wars 2 and one crash from the Titanfall Beta which had gave me a frozen screen with artifacting and reset my computer.
I have a video of the artifacting happening in Guild Wars 2 if anyone is interested. http://www.youtube.com/watch?v=DzpjO5d4izI
I have also installed MSI Live Update 5 to install any of the latest utilities and drivers from MSI.
Overclockers say that they tested it for 24 hours on benchmark software, Battlefield 4 and the other latest games, they also seem to not care about my having problems on Guild Wars 2 and League of Legends because they are either old or do not run on an intensive engine such as Frostbite from BF.