sivakotarib4u :
Thanks Guys for lot of inputs,
But i havent got any conclusion either AMD or Nvidia.
My PSU is Cooler Master Thunder 600Watt.
i guess the discussion moved away from the Graphic cards to CPU performance, as im aware my rig is not an outdate for those cards. Please give me some suggestion regarding cards..
From a pure performance perspective form best to worst in the below order.
HD7950 > GTX660ti > HD7870 LE/XT > GTX660
From price/performance perspective best to worst in the below order.
HD7870 LE/XT > HD7950 > GTX660ti > GTX660
From power/performance perspective best to worst in the below order.
GTX660 > GTX660ti > HD7870 LE/XT > HD7950.
Now noise will depend on the card you get. I would not suggest a reference design. Get a Sapphire Vapor-x or Dual-X for the 2 HD7xxx cards. And an MSI Twinfrozer for the GTX6xx cards if you like quiet and cool cards.
My suggestion is get an HD7950 if you got the cash, if not, the HD7870LE/XT.