leaked cayman spec:

shocking 1920shader with 3.5tflops if this is true, then the die size will be really big...hopel it wont cost as much as gtx580..
there are also rumor that hd6970 are faster than gtx580 
if direct comparison with hd6870, the hd6970 have more than 70% increase of raw shader power
AMD FERMI anyone? 

There's no problem in doing so. You do not need two cards with identical coolers to CrossfireX / SLI.

.

You will need the card in the same series though e.g HD5800 Series.

yes u can.

for more info, google for crossfire-x compatibility chart.

It would be hard to imagine 6990 will be. and I dont think it will be dual 6870, because thats gonna be equal performance with 5970.

Base on this fact, Cayman will not beat 580 because it need to fit the TDP for dual card. but AMD might just use 6990(dual underclock cayman) to beat GTX580.

What im worry is the price and TDP.

OK tq.. but wat is the 1st thing i nid to do when i plug in my another GC then joint the CF cable..
Start my pc and ...??

SOrry.. 1st time Cf-ing..
Googled but cant understand ..lol

AMD Cayman pushed back to December 13

Still before Christmas

We just got a nice little tip from one of our trusted sources that AMD just gave an official new date for Cayman launch, the 13th of December. This means that despite a brief delay, Cayman will still be on retail/e-tail shops before Christmas, and if the performance is right, will end up to be the fastest single GPU card this year.

The new date was given by AMD officially and probably sent to all partners and selected editors. It looks like the problem is quite real and partners mostly don't care about this delay as they have enough other cards to sell and as long as the card comes before Christmas. According to what we know, partners didn't recieve the final BIOS or the final driver for that matter, but that should hopefully change by the end of the month.

We are quite sure that we'll hear more about AMD's Cayman once it gets its final driver, as until then, the performance details are purely speculative and any early benchmark figures seen so far should be taken with a grain of salt, as proper drivers could squeeze out a bit more performance.