With the current generation of Radeon videocards, ATI has taken a fresh approach to the way CrossFire is implemented. As you've probably noticed, there are two 20 pin connectors on the top left hand corner of the videocard. These are similar in appearance to nVIDIA's SLI bridge connectors.
ATI/AMD has given up on the concept of Master and Slave videocards, and those cumbersome external connectors Crossfire used to involve. In the current and future generation of Crossfire compatible videocards, all parts are treated equally and are hooked up internally.
ATI employ two flexible flat-wire Kapton cables between each of the videocards' Crossfire
connectors. Both bridge connectors must be used in order to take advantage
of ATI's CrossFire
To enable ATI CrossFire, the first step is to install
two Radeon videocards with the same core and memory configuration (although it
doesn't have to be the same brand). Each crossfire compatible videocard should comes with it's own flexible CrossFire bridge connector, and both must be connected. Once the hardware is installed, the next step is to boot up Windows and load the AMD Catalyst Control Center. In this software you enable CrossFire mode, then it's just one more reboot and you're all set for gaming glory.
The small tabs allow you to grasp and remove the
ATI Crossfire connectors without much difficulty. Both bridge connectors must be used in
order to enable CrossFire
ATI/AMD CrossFire technology is not as
pervasive as nVIDIA SLI, which is one of the reason why AMD is still going
through teething problems with its CrossFire setups. Support overall is good,
but with certain titles (Capcom's DX10 Lost Planet comes to mind), performance tanks
when CrossFire is enabled. If that happens you'll have to patch the game
itself or the Catalyst drivers. Depending on the game the patches or driver
updates will be available from either AIT or the game developer
For example, PCSTATS has to patch Lost Planet with a file
from AMDs website before the game would run correctly under Crossfire. Since
then the 7.8 Catalyst drivers have addressed the issue. There are still spotty issues with DirectX10 game
titles like Call of Juarez and Lost Planet which can both experience AA problems. Half Life 2 and
games based on that engine, occassionally suffer excessive fog.
Up next, a quick look at the Radeon HD2900XT core and then
PCSTATS dives right into the overclocking!