This issue is common with advanced warfare and the R9 270 Series graphics cards, and it seems to be an issue with Activision. If this is the only game which is effected, you know where the issue lies, if this is across multiple games we can explore other possibilities. If you haven't upgraded to the latest AMD driver, that would also be recommended - found here -
http://support.amd.com/en-us/download
before updating any driver of AMD's use the clean driver uninstall utility -
http://support.amd.com/en-us/kb-articles/Pages/AMD-Clean-Uninstall-Utility.aspx