[Thayalan Paramasawam] "i am using radeon hd 6770 graphic card."
Advanced Micro Devices, Inc. (AMD) is the company that makes the Radeon HD 6770 graphic card (i.e. they bought out ATI) so
Advanced Micro Devices, Inc. (Juniper) is your graphics card and the setting you should be using.
~jr
http://www.johnrofrano.com
http://www.vasst.com