Note: Note that this technique only works if the hardware manufacturer implements it. I can't give a percentage of accuracy, but I would guess the big players would implement it. If it's not implemented, Windows will generate a unique number instead.
Method 1 - Device Manager
Open the Windows Device Manager. Find your video card under Display Adapters. Double-click on it. Under the "Details" tab, select the "Device Instance Path" property.
Method 2 - WMI
Using WMI, at the command line, run the following command.
wmic PATH Win32_VideoController GET Description,PNPDeviceID
Method 3 - Use a Tool
A program like SIW will grab the PNP Device ID for you, but it won't do the parsing for the serial number.
Looking at the PNPDeviceID value, break it up by "\".
- The first piece it the bus type. For me, it is PCI.
- The second section describes the card. There's a vendor code, model number, etc.
- The last section contains a number separated by ampersands. The serial number is the second number in that list, formatted in hex.