4850x2 uses less power than 4850 in CF... (Cause it only has to power 1 board, along with some other smaller things that are combined, requiring less power). You should be fine.
Which Antec 550W? If it ran 4850 crossfire fine, the 4850x2 will be no different. But if it is one of the older Antec 550W units, I might advise against it.
The minimum's are in place as a safe measure because the majority of power supply's at 650W will run this card. A 550W will be fine, especially if he ran 2 before in xfire. Just make sure your not loading up on HDD and ODD, and it should be fine.
Originally Posted by Diabolical999
The minimum PSU requirement (on the box) for 1 4850 X2 is 650w. Not gonna speculate whether 550w will cut it, I'd just go by the box though.
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