This release of Catalyst introduces software CrossFire support for any combination of Radeon X1900 and X1950 installed in a system running either the Windows XP or Windows XP Professional x64 Edition operating system.
A performance increase is noticed in Call of Duty 2. Performance improves as much as 12.5% at 19x12 settings and as much as 10.5% at 12x10 settings on X1900 Software Crossfire configurations. Largest gains seen with 4xAA enabled.
You can grab them over here.