How do I know how much Video RAM (VRAM) is installed on my computer?
To check the amount of VRAM (video RAM or display memory) installed on the computer,
1. Click on the Start button in the lower left hand corner of the desktop. 
2. Select Run and type "dxdiag" in the input box. Select  OK. 
3. The DirectX Diagnostic Tool dialog box will open with a series of Tabs across the top.  Select the Display tab.  (If the DirectX Diagnostic Tool does not open you likely need to install DirectX onto your machine. 
4. On the left side box you will see Device properties for your display card.  One property will show you the Approximate Total Memory in megabytes (MB).