Need a quick answer before i got out and buy this graphics card

http://us.ncix.com/products/?sku=69828&vpn=FX787ACNFC&manufacture=XFX&promoid=1312

or this

http://www.newegg.com/Product/Product.aspx?Item=N82E16814150590

Will the 7950 add decent performance or is the 7870 ghz core edition just as good.

Will want to play games at 1080p etc etc.

Will i see a depression of performance if i go with the 7870?

I only plan to use one monitor and would like to save the cash if i could.

Does the 2GB ov 3 GB make a difference?