ATI'S ATHLON 64 CHIPSETS had a rough time winning over enthusiasts in the Socket 939 era. Enthusiast-oriented motherboards based on the Radeon Xpress family weren't as plentiful as those sporting one of Nvidia's many nForce4 variants, and for good reason. ATI's SB450 south bridge was short on features and plagued with I/O performance problems that prompted many mobo makers to use an alternative south bridge chip from ULi. ULi was eventually purchased by Nvidia, putting additional pressure on ATI to nail the design of its next-gen SB600 south bridge.

That pressure apparently motivated ATI's chipset team, because it delivered a surprisingly solid SB600 south bridge back in May as a part of the CrossFire Xpress 3200 chipset for AMD's new AM2 socket. The I/O performance problems that had sullied previous ATI chipsets were nowhere to be found, and the Xpress 3200 delivered much lower power consumption than Nvidia's comparably gluttonous nForce 590 SLI.

A few months have passed since the CrossFire Xpress 3200 launch, and the chipset is finally starting to appear in retail motherboards from ATI's partners. A couple of board samples have also appeared in our labs in the form of ECS's KA3 MVP and MSI's K9A Platinum. Keep reading to see how well each has implemented the CrossFire Xpress 3200 chipset on Socket AM2.