@ Maddy_AzAd - get the 1GB GDDr5 version - if you can't find it opt for 1GB DDR3 version and a new PSU is still required.
If you are using XP the gfx card will wok but you won't get any DX11 feature as XP can handle DX9.0c at max - so better upgrade to win7 or at-least xp-sp3.
Check InfiBeam: Gifts to India | Online Shopping India | Apparel, Books, Cameras, Watches, Mobiles, they have a Sapphirw HD 6670 1GB DDR5 for 5.5k. Get it befor it goes Out Of Stock.
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