Have you tried the drivers from Asus website specifically for the AMD R9 GPUs?
http://www.asus.com/Graphics_Cards/R...T3GD5/#support

For some reason there are issues with the older official drivers, especially with the earlier drivers from Asus website. I have yet to have an issue after upgrading to the ATI Display Driver 13.251WHQL from the Asus support site. And yes, I do remember the yellow artifacts, especially being annoying!
I have owned 2x AMD R9 280X DC2 TOP 3GB running in Crossfire since they were first released back in October. The official AMD drivers I have found are very hit/miss for these cards, and tend to stick with the Asus configured drivers since they are most stable + offer better performance/color control.
Also remember that SOME official drivers will NOT list the GPU as an R9 280X, but instead a HD7970. Though they are basically the same cards, there are stability issues when you try running games like extreme flickering, artifacts, missing textures, etc. These issues will appear in other games beyond FF14, so it's most likely a driver issue. Keep trying various drivers, however, almost everyone who bought this card or another Asus based AMD R7/9 series card that has had this issue has moved to official Asus drivers simply because Asus does configure them to each card instead of AMD doing a mass amount.

Current computer setup:
Mobo: Asus Maximus VI Hero
CPU: Intel i7 4770k @ 4.0Ghz
RAM: G.Skill Ripsaw X DDR3 32GB @ 2400
SSD: Samsung 840 Evo 500GB
GPU: 2x Asus R9 280X DCU2 TOP 3GB -> CrossFire w/ Asus ATI Display Driver 13.251WHQL -> Using Optimize 1x1 for best FPS through CCC
PSU: Seasonic X-series 1050W
OS: Windows 8.1 Pro x64