As i mentioned above , it's the PSU 90% sure.
I used to have my videocard overclocked since i play on an ATI HD 3850 AGP videocard ( no money for new system yet)
I play flawlessly on high settings with it , but my PSU ofcourse got older and after a while cooling of the PSU gets less.. u know dust etc.
I felt the psu.. touched it and i did notice it was pretty hot ( i have an open case , so i can check whatever whenever , for airflow reasons it's open)
So i brought my videocard back to old factory settings and my problems were gone.

I have to mention that it indeed only happens with FF14 , wich is strange.. and i am realy not sure why FF14 would draw more power as other games.
Except that FF14 uses mostly the graphic card and less CPU , wich could explain the blackout. gpu draws too much power