On some computers, the graphics controller name is listed during the Power On Self Test (POST). Press the 'Pause/Break' key to pause POST if the message displays too quickly.
Graphics Controller or Chipset Markings
If the methods above are not successful, you may be able to identify the graphics controller by looking at the markings of the graphics controller or chipset that is on your motherboard or graphics card.
Caution: Opening the computer chassis may cause damage to the computer. For more information on using this method, see Graphics Controller Markings.