by AverageJoe » Thu Jun 11, 2015 4:53 am
Could either be: 1) corrupt WoW installation. 2) out of date graphics card drivers. 3) overheating graphics card.
If 1), try uninstalling WoW, deleting any loose files that remain after the uninstallation, and reinstall WoW to see if it fixes the issue. If not, 2) check your graphics card manufacturer's website for any new drivers and download/install them to see if it fixes the issue. If not, 3) download some software that monitors the temperature of your graphics card and see if it's overheating while trying to play WoW.