If you  want to know the details about built-in graphic card/external graphic card you connected to your Computer then can use GPU-Z  freeware portable tool which displays the adapter, GPU and display information and info of Over clocks, default clocks and 3D clocks (if available) on its program window. Moreover you can click on camera icon on right-corner of program to save a screenshot of displayed information to your system in GIF format.

GPU-Z

The technical  information displayed by GPU-Z includes: graphic card name, its revision number, GPU name, technology, released date of card, Graphics BIOS version, GPU device ID, Memory type, driver version , GPU clock frequency , default clock frequency, multi-GPU technology enabled/disabled status if enabled shows number of GPUs that are working together and more.

GPU-Z supports NVidia and ATI cards, works on Windows 2k/XP/Vista/7.

Download GPU-Z