Video card upgrade

[intelfanb0y]

Hey I bought this PC last year
http://www.cybertronpc.com/customkititems~kc~gm2242a~group~play~cat~gamers.htm
with that config and i want to upgrade the card which would be better the one i have in crossfire this one http://www.ncixus.com/products/?sku=103516&vpn=AXR9%20270X%202GBD5-A2DHE&manufacture=PowerColor&promoid=1242
or this one http://www.ncixus.com/products/?sku=91083&vpn=11216-00-20G&manufacture=SAPPHIRE&promoid=1242

 

[Golcsae13]

The R9 270X is better than the crossfire configuration.

 

[intelfanb0y]

thanks for quick answer but why?