AnandTech: AM2 Motherboards-Part 4: ATI Crossfire Xpress 3200

Part 1, Part 2, and Part 3 of our AM2 roundup examined six AM2 motherboards based on the nForce500 family of chipsets. Four were based on the top-end 590SLI chipset and two were based on the mainstream 570SLI chipset. This installment, Part 4, looks at the first two AM2 motherboards to reach retail that are based on the ATI RD580 chipset.

The RD580 was introduced with great excitement in early March, but the market was still Socket 939 Athlon64 running DDR memory. With the AM2 launch just a few months away, everyone knew ATI had designed RD580 for Socket AM2 and DDR2. In fact many manufacturers skipped producing an RD580 Socket 939 board because the life would be so short. Those manufacturers said they would wait for AM2 to provide RD580 chipset solutions to the market.

AnandTech reviewed the ATI RD580 Reference board for AM2 on June 1, and boards were expected to start appearing in the retail channel in just a few weeks. That didn't happen, and it has taken from June 1 to mid-August to finally see the first retail RD580 boards for AM2 and DDR2. This is the all too typical ATI chipset delays that have killed just about every ATI chipset introduction to date.

This time around, however, the stakes are much more interesting. Several weeks ago AMD announced it was acquiring ATI. That gives us every reason to expect - down the road - that ATI chipsets will be the standard AMD chipsets just as Intel has their own chipsets for Intel processors. Since the AMD announcement it has been even more frustrating that it has taken ATI so long to reach retail with RD580-based motherboards supporting AM2. We are happy to announce they are finally here, and you should be able to buy RD580 chipset AM2 boards beginning this week. While there are only a few early RD580 boards, we have been told that many more are on the way. It will be interesting to see if the performance justifies the wait for RD580 chipset motherboards.

RD580 is similar in feature set to the top-line NVIDIA 590SLI chipset. Both support dual X16 GPUs - NVIDIA with SLI and ATI with CrossFire. Both also represent the top-line chipset for each respective manufacturer. Physically the chips differ in ATI RD580 being a low-power single-chip North Bridge and NVIDIA 590SLI using two different chips to each provide an X16 PCIe slot to the architecture. NVIDIA 590SLI provides I/O off the chips that also support the dual X16 PCIe slots. ATI uses a more traditional South Bridge with the RD580 to provide I/O.

The South Bridge has been the weak link in past ATI chipset designs. Best performance was provided by ULi South Bridge chips while ATI's own SB450 only supported SATA1 and was plagued by slow UBS 2.0 performance. Beginning with RD580, ATI can now provide a complete and up-to-date chipset by combining RD580 with their new SB600 South Bridge. This came none too soon, as NVIDIA bought ULi in early 2006 and found themselves in the position of supplying their major chipset competitor with the South Bridge chips that made the ATI chipset competitive. With SB600 now in the market, ATI (and AMD) can now provide a complete single source chipset to motherboard manufacturers. This also means ATI is no longer dependent on their major competitor to provide a complete and competitive chipset for the A64/AM2 platform.