gtx280 oc2 / ati hd4780x2

hallo i was wondering wich is better card for fsx anyone can answer me plzthanxi have gtx280 when i run the fsx sometime i am getting some shadow on my screen and some number yestarday when i start fsx over usa i got the fsx logo on my screen during flying it appeare for 5 second and it is gone and the ground sometime become black square(i am usuing utx usa with last patsh) so i wanna make sure if my video card is working properlly or not so any idea how can i cheek my video card and make sure 100% that is working good and no manifucture problem(i bought this card 7 days back so if it is broken i can still send it back)thanx