Hi there!
In most cases, the computer manufacturer has already configured the system to use the maximum amount of graphics memory that is possible for your particular computer model. Sometimes you can change these values through BIOS level.
See the following URL for more information:
Graphics memory frequently asked questions
http://www.intel.com/support/graphics/sb/CS-029090.htm
Check with your computer manufacturer if there are tips on increasing the amount of graphics memory for your computer model.
Thanks
Allan