I have a squad mate who used xFire on a pair of 19xx cards and wasn't impressed. He couldn't get them to both workBut he got that Crossfire kit from me and on my system they worked fine and very fast, faster in a couple of games than my 7900 GTX OC SLI rig which was on RMA at the time and for many weeks, BFG ran out of replacements, that early 7900 OEM problem. When the SLI rig came back fixed I had to decide which rig to keep and I chose SLI only because the Crossfire kit ran hotter and noisier
I've never teased him about why he couldn't get the Xfire rig to work, unusually for me but then a wingman knows when to keep schtum. Plus he's on safari Devon way so has no right of reply
Crossfire's lovely Brigs, smashing kit. Not much in it between ATI/AMD and Nvidia's offerings.
But the 8800 Ultra is quite another animal: enormously powerful, fast and silent like a ninja rhino with contacts. Av would definitely call it blistering. Bludgeoning
Ming