Guru3D informed us they have posted ASUS ATI Radeon X1900 XT Crossfire review.

The Crossfire experience itself ... it's difficult to form an opinion about it. Just like the high-end SLi combo's the solution is massively expensive as all the components in your PC have to be right. Especially when you are doing the high-end Crossfire setup as we have tested today. I'm not even talking about the money here but the stuff that you need to make this rig run optimally. You need the 2x 16X PCI-Express graphics slots, you need the high-end power supply and most of all do not forget you'll need the fastest processors available to feed that Crossfire driver enough data to make the cards work 100%

Our test results today have shown that majority of games will run into the dreaded CPU bottleneck if you play games below 1600x1200. The dual X1900 XT's really want and can go faster yet even our AMD64 Athlon FX-57 processor (which still is the fastest single threaded gaming processor that money can buy) is not able to kick the crap out of the two X1900 XTs. Now do not get me wrong, as the performance is simply so darn fast .. you won't believe what you are seeing but .. it could be even faster with a better CPU or a future game from 2007/2008 :)

My advise to you for a Crossfire X1900 XTs solution is that both cards have to pull there "cold air" from the inside of the PC. So you need to make very sure that your PC is well ventilated as when the cards are peaking (both of them) at 80 Degrees C temperatures on the graphics core, and again .. it's two of them. An unsettling part was noise .. at boot up it's really bizarre. Things will definitely be more quiet once windows has finished booting as the RPM of the fans will go to a silent level. Yet during gameplay occasionally you will hear the noise levels coming from the two fans really rather audible.