I dug up some of your old posts on another forums and it seems like this is more 700w?
If you mean I said the PSU is a 700W, check the date.... I was an idiot up until around 2010.
And I didn't notice, but yes your Alienware PSU should actually be quite nice. Not as efficient, but certainly better built and probably with better performance, and should handle Crossfire 6970s easily.