Hm...I have a HD5770 and run the system at comparable settings (my background quality is 3 and my texture settings are all standard, but I'm running in a 1920x1200 window). Based on my experience, overriding the settings in the Catalyst Control Center or whatever it's called now by changing them from "Application Specified" can affect your FPS in FFXIV in positive and negative ways. You may get more FPS by setting them all back to application default.