hbkneeraj :
I don't want to spend a lot of money on a new psu..So I just want to buy a least expensive psu ex CORSAIR CS450 to use along with my exisiting 250w psu...I just want to know how much 'AMP' does ROG matrix 7970 require for proper functioning...
You're not very tech-savvy are you?
You cannot run TWO power supplies because they each need a motherboard to control them. If you don't want to spend a lot of money on a new PSU, don't expect to get a good PSU. Don't expect to be able to run a high-end video card and don't expect to play high-end games at high-end settings. I would go so far as to say "Don't ever open your computer case, someone like you is the kind of person who manages to fry things with static electricity...