ATI finally released the X1800XT crossfire boards, and performance appears to be pretty solid. As is usual with new product launches, if you know where to look, you can find them a bit early. This early peek has numbers to boot, check here, look at the screenshots on the right side. The bonus bits are the numbers,
System Properties,
one card and
crossfire.
For those only interested in the short story, with an FX-57, it scores 8663 and 12848 with one and two cards respectively. Both scores are not fully qualified benchmarks, but looking at other scores online, it looks like they will come up a hair short of the 7800GTX/512.
In a strange turn of events, the X1800XT is now available and the 512 is not. The 512 is more expensive, but also higher performing. The 7800GTX/256 is cheaper, available and lower performance. None of the aforementioned cards can be considered cheap though. A call to Monarch says they have over 100 in stock, so they should be plentiful for the next week or so, but I would recommend against waiting if you must have one, there is no word yet on when the next shipment is due, and these are almost guaranteed to sell out.
Source : TheInquirer