MSI HD6950 2gb Crossfire Twin Frozr III PE/OC or MSI Gtx580 lightning

[Parabolax-y]

Hello, I'm going to be building a computer next month and was wondering which way to go.

2 http://www.pccasegear.com/index.php?main_page=product_info&cPath=193_1179&products_id=18330 in Crossfire

or

1 http://www.pccasegear.com/index.php?main_page=product_info&cPath=193_1170&products_id=17070

How hot would the 2 6950s get and how much more power would they need?

Also, which option would you choose and why?

 

[monsta]

MSI GTX580 Lightning, its a great card, you can't go wrong.
One card is better than two for heat and power and also for quiter operation.

 

[Maziar]

2 6950's are faster but I "personally" prefer 1 580 because it runs cooler,quieter and has less power consumption(and gives you the option to add another card later)

 

[hellfire24]

+1.6950's are faster but single 580 is better.less consumption,noise,heat etc.i have lightning xtreme 3 gb version.no problems.