Crossfire Xpress 3200 For Intel
The launch of ATI's Crossfire Xpress 3200 for AMD processors was almost exactly one year ago, so one can't say that ATI/AMD has been particularly quick. Still, you have to take into consideration the fact that ATI chipsets for Intel processors have never played in a league with Intel chipsets, and it also took Nvidia some time to refine its Intel chipset portfolio until the firm arrived at where it is today: looking into Intel's eyes in the enthusiast space. The interesting part of AMD becoming a chipset supplier is not the fact that this product powers the processors of its rival, but rather AMD's statements indicating that it does not want to be a chipset supplier. Well, it seems as if the company inherited this business, and it's not going to be any easier under a different name.
The Crossfire Xpress 3200 for Intel is what many of you know as RD600. It was designed to offer as many as three x16 PCI Express slots: two for ATI graphics cards in Crossfire dual mode, and the third one for a physics accelerator card, powered by an ATI card as well. But ATI did not reach for the stars: the x16 slots for graphics are powered by eight PCI Express lanes each. The third slot runs four lanes if northbridge and southbridge are connected with four lanes as well, so that's eight more lanes. Compared with Nvidia's 40 lanes this is not too much, but based on our experience, you don't really need the full bandwidth of 16 PCI Express lanes per graphics cards as long as they communicate directly via other interfaces. This is the case for all high-end products.
The dual channel DDR2 memory controller officially supports speeds up to DDR2-800, it is up to the motherboard makers to decide if they want to support DDR2-1066 as well. ATI/AMD developed the whole chipset with overclocking in mind: it features flexible memory clocking, and independent clock speeds for FSB, PCI Express and DDR2 RAM ensure maximum flexibility. Crossfire Xpress 3200 for Intel is based on a 90 nm process, which enables a low heat dissipation and thermal design point low enough to cool both chipset components passively.
AMD SB600 Southbridge
AMD's SB600 southbridge links to the RD600 via ATI's A-Link Xpress II interface, which is a high-speed interconnect based on PCI Express. There is a total of four PCI Express lanes available: depending on how many lanes are being used for other components (or x1 PCIe slots), the A-Link Xpress II interface can link using one, two or four lanes. There is a 32-bit PCI host controller for up to six slots, as many as five OHCI USB 2.0 host controllers for up to 10 ports, a four-port Serial ATA II Advanced Host Controller Interface (AHCI) controller with Native Command Queuing (NCQ) support and maximum bandwidth of 300 Mbit/s per port, a High Definition audio controller, and a single UltraATA/133 channel for up to two legacy storage devices.