4850 does not support DX11. 750 watt is enough for the crossfire.
Newer tech is only worth it if you use it! Do you plan to run eyefinity over more than one monitor or use DX11 (win Vista and 7 only) then it is worth it.
Add me to the 5830.
Agree with the above logic.
On paper your giving up some gpu horsepower.
But 1 more powerful 40nm gpu, gddr5, as a enthusiast, I sleep better with newer tech
Its very similar to the argument, You can still get a 4870 for 150.00, do you get 2 of those instead of a 5850 ? http://www.newegg.com/Product/Product.aspx?Item=N82E168...
I would not , sacrifice slight power to gain advantage of having only 1 video card and newer tech.