4850 to replace 3870?

[Tacoboy]

I'm expecting my second 3870 graphics card to arrive tomorrow, but now I'm having second thoughts on running two 3870 in a crossfire as the second card usually covers the SATA ports on most motherboards.
So i'm thinking of just getting a single 4850 card.
How much faster/better is a 4850 over a 3870?

 

[Dekasav]

I believe the 4850 is about equivalent to the 3870X2, which is the two 3870s in crossfire. So much faster.