Hi, i know there are reviews out there talking about crossfire, but i wanted to make sure cause i was planning to do crossfire with either 5770 or 4870 and i have a OCZ Z-SERIES 550W 80+ Silver Certified 24PIN ATX 12V Afc Power Supply W/ 120MM Fan. Would that be enough? And also i didnt buy the Mobo or CPU yet so i was wondering if i wasnt going for any high end mobo/cpu build and just buying regular parts just for gaming, around how much watts should i need for crossfire? Thanks.
I wouldn't do the 4870 on that PSU. Sure it will probably run it, but it'll be pushing it. The 5770 uses much less power (and is cooler) and would be a much better fit for that system, and its much more current in its technology with DX11 and eyefinity etc. Its also probably cheaper right now to get teh 5770 than the 4870. You should have enough PSU for a decent system with that PSU and the 5770's Xfire.
You should only considering crossfiring an HD4870 if you already got one. But if you are buying two new cards, go for the HD5770. It performs only a little below HD4890 and consumes less power too so the cost of ownership is much less in the long run.
I myself already got an HD4890 but is now torn between buying a 2nd HD4890 ( if I can find one ) for about $210 ( where I came from ) but not have eyefinity or spend around $420 for an HD5870 with eyefinity.