As Intel's Core 2 Duo processors are growing increasingly more popular, there is also a growing amount of users that are opting for a Crossfire setup. This will not come as a surprise, as the popular Intel chipsets do support the ATI system, but not nVidia's SLI. For a while one was stuck to the high-end 975X chipset, but recently Crossfire also works with cheaper mainboards based on the P965 chipset. However, how much performance will you loose?
nVidia is acting out a strict policy for the SLI technology: SLI only works with mainboards based on a nVidia chipset. This restriction has not been made because of some technical background, but seems to be a pure marketing decision: while using hacked drivers SLI has been proven to work with other boards with two VGA slots, but with the official nVidia drivers one depends on the nVidia chipset.
Until now this used to be not much of a problem, as gamers automatically tended to buy an AMD based system anyway. And in addition, nearly all higher end AMD mainboards carry in a nVidia nForce chipset.
But for nVidia these days seem to be gone: with the introduction of Core 2 Duo processors crowds of gamers have made the switch from AMD to Intel. Also keep in mind that Intel supporting chipsets are not nVidia's speciality: during the first half of last year the market share on sold AMD mainboards showed a luxurious 42%, but for Intel chipsets nVidia scored a lousy 0%. However, while writing this nVdia finally has made a slight return with the Core 2 Duo compliant nForce 650 and 680 chipsets.
So nowadays gamers opt for Core 2 Duo and in most cases Intel based mainboards. ATI makes profit out of this recent gamers choice: as the Crossfire technology has been developed to work on all chipset brands, gamers are able to assemble two ATI graphic cards on their Intel based board without even the slightest problem.
Recently a Crossfire setup demanded a mainboard with the high-end Intel 975X chipset, as these mainboards contain 16 PCI-Express lanes for the north bridge which can be divided into 2x 8 lanes. Therefore one single chip is able to control two graphic cards. Cheaper Core 2 Duo mainboards, based on the P965 chipset, do not allow this trick. Because of this those mainboards recently were not Crossfire compliant.