ATI made it clear at the launch of their CrossFire Xpress 3200 in March that it would be more than just a Socket 939 chipset. The new ATI dual X16 chipset would be launched for Socket 939, but it was designed from the ground up for AMD Socket AM2. ATI is now showing how well the CrossFire Xpress 3200 performs on the new AM2 socket with DDR2 memory.

The AM2 launch for ATI is also an important launch of new technology for ATI. AM2 is the first time we have seen the new ATI SB600 Southbridge, and it's coming to market none too soon. ATI's Rx480 and RD580 for Socket 939 were somewhat hampered by the outdated feature set of their SB400/SB450 Southbridges. Both were excellent in IDE and standard SATA performance, but they lacked SATA2 3.0Gb/s support featured in competing chipsets; SB450 also was criticized for lackluster USB 2.0 performance compared to the competition.

Most manufacturers who went to market with ATI's SB400 or SB450 were penalized with low sales, so much so that most manufacturers in the RD580 launch this past March went with the compatible and up-to-date ULi M1575 Southbridge. This solution worked well, but NVIDIA purchased ULi and ULi M1575 Southbridge chips have become scarcer in the marketplace. ATI has been promising for almost a year that SB600 was coming and would fix the Southbridge concerns. With today's launch SB600 is finally a reality. This is important for ATI since manufacturers can now use a full ATI chipset solution that should be well-received in the marketplace.

Through development the latest ATI chipset was called RD580. When ATI launched their dual X16 Northbridge for Socket 939 in March the official name became CrossFire Xpress 3200. RD580 for AM2 carries the same name - CrossFire Xpress 3200 - with the addition of AM2 to identify the board socket. This is in contrast to NVIDIA's launch of nForce5 which uses a die-shrink "Northbridge" MCP with added features and an existing "Southbridge" C51 to provide the second X16 PCIe video slot.

With the introduction of the SB600 Southbridge with the RD580 AM2, ATI has made revisions to their chipset lineup. The features listed in the chart below are not all provided by the RD580/SB600 chipset, but are ATI recommended configurations for the target market segments. The top-end recommendation is also the configuration of the RD580 AM2 Reference board. Page 2 provides details of the features you will find in the SB600 compared to competing chipsets.

Xpress 3200 now covers RD580 Socket 939 and AM2. RD480 is now combined with SB600 with the new name Xpress 1600. The integrated graphics solution, based on RS485, is now marketed as Radeon Xpress 1150.

At launch, ATI was hesitant to provide reference boards for testing since it will still be several weeks until retail 3200 AM2 boards will appear in the marketplace. ATI was preparing for the original AM2 launch date of 6/06/06 at Computex. Several weeks ago AMD decided to move the AM2 launch back to May 23rd, and directions could not be changed that quickly. Considering the date changes were by AMD, it is understandable why ATI will have a slight delay before retail AM2 boards appear on the shelves.

CrossFire Xpress 3200 for socket 939 brought dual X16 PCIe slots to the ATI chipset. This made the ATI RD580 fully competitive with the top NVIDIA chipsets for AMD with the exception of a few I/O features. Socket 939 RD580 was still paired with SB450, which had the disadvantage of no SATA II support and lackluster USB2 performance.

CrossFire Xpress 3200 AM2 aims to make ATI fully competitive in features with the top NVIDIA offerings for AMD. With AM2 comes the long-awaited SB600, with support for SATA2 and much improved USB performance. ATI would tell you, however, that RD580 is more than just competitive with the best from NVIDIA.

The new ATI dual X16 is the first of the type to implement dual X16 with a single chip. The NVIDIA solution uses two chips with a potential communications roadblock between the two chips that were really developed for other applications. NVIDIA states there is no performance loss in their design. However, NVIDIA is also planning to move to a single chipset supporting dual X16 PCIe video lanes later this year. NVIDIA states that move is for cost savings.



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  • Wesley Fink - Thursday, June 01, 2006 - link

    1X Increments corrected.

    We did not have audio performance data for nVidia chipsets in the 590 launch review, but it will be included in our roundup of 6 AM2 boards which is in process. I have added numbers for the Foxconn ( nForce 590) HD codec for reference. Foxconn is the nVidia Reference board.

    The board photo was captured at 12 Megapixels. Unfortunately, the "Save for Web" feature in Photoshop which gets the image to a reasonable file size for posting a 1280 image compromises sharpness at higher resolutions.
  • Trisped - Thursday, June 01, 2006 - link

    Thanks for the Foxconn numbers.

    So you used "Save for Web" and lowered the quality so it would be easier to download? That makes sense. A 43k file is much better then a 1M one.
  • JarredWalton - Thursday, June 01, 2006 - link

    Or 422K vs. 5+ MB. ;) Reply
  • lopri - Thursday, June 01, 2006 - link

    I truly appreciate AT staff's responses to my questions. It cleared so many things that I questioned while reading the review, so now I'm understanding better.


    the fact is DDR400 was the fastest memory standard for DDR. Anything higher was overclocking. For DDR2, we have DDR2-800 as the current highest standard speed

    This is actually the only possible explanation that I could think of. You're right in that DDR400 is the fastest JEDEC approved speed. I sort of guessed but still, considering the ammount of memory reviews you've done in the past, thought a bit stranage. But thank you for explaining. Request, however: Please do a out-of-the spec DDR vs DDR2 reviews in the future. :D This can be a big factor for people who actually consider upgrading.


    AMD introduced this platform with very conservative timings and tables for the board and memory suppliers to follow. We expect to see 1T timings at 800 later this year as AMD "massages" the memory controller. I ran tests at DDR2667 1T and they were basically the same or slightly worse than DDR2800 at 2T with all other settings being equal. The problem is we cannot run tRP and tRCD lower than 3 currently so any advantage of 1T is being wasted due to higher latencies. On a couple of our review boards we could also run DDR2800 at 4-4-4-15 1T but the 3-3-3-13/9 2T setting provided better memory bandwidth and lower latencies overall. We are still testing various memory settings as each board has been a little a different in optimizations made by each supplier. We will have a separate review on EPP and Memory settings for AM2 in the near future.

    Again, I appreciate the explanation. Not knowing about DDR2 much myself still, I could not have known it when reading the review. It'd have cleared up some misunderstanding if you have mentioned the 1T/2T issues in the review (like above), it'd have helped a ton to understand. I'm sure there are many different traits of DDR2 compared to DDR, without such knowledge I could not help but questioning. Thank you, Gary.

    Still the 1T/2T issue on AM2 is somewhat disappointing. (Not reviewers' fault) I have a bad feeling that AMD's IMC won't be able to handle 1T for DIMMs faster than DDR2-800, even with future revision. :( For entire lifespan of Socket 939, they couldn't get 4 sticks to run @1T timing.. (except a couple going-around of DFI's)

  • lopri - Thursday, June 01, 2006 - link


    Our Corsair or OCZ PC8500 sticks will run at 3-3-3-9 2T at 800 with a small voltage increase to 2.2V easily although the memory is rated at 5-5-5-15 2T. I am working on a single versus dual channel DDR2 article at this time, cutting to the chase, single channel DDR2 with fast timings will provide up to 98% of the performance of dual channel DDR2 under the same conditions. It might be something to think about when looking at $350~$500 DDR2 2GB kits.

    Also if this is true, it's an absolutely fantastic news. Please let us know the detail as soon as you can. Thank you.
  • DigitalFreak - Thursday, June 01, 2006 - link


    ATI did not need to develop a new chipset for the new Socket AM2. Why then has it been so difficult for ATI to have AM2 chipsets ready for launch?

    Maybe they didn't need to develop a new North bridge, but the South bridge is another matter. With ULi supplies drying up, it would have been extremely stupid to use the SB450 yet again.
  • Myrandex - Thursday, June 01, 2006 - link

    It was stated that the ATI solution was better tahn the ULI and less than Nvidia, however in the graphs it was less than both, although very close to ULI.
  • Wesley Fink - Thursday, June 01, 2006 - link

    The statement is correct. Going back to review notes there was a typo in the chart creation which has now been corrected. USB throughput for SB600 is 241.6 and not 231.6 as shown in the earlier chart. Reply
  • Alyster - Thursday, June 01, 2006 - link

    I just wonder if SB600 will be available on 939 boards in future. I'm going to purchase ATI based MSI-RS482M4-ILD mATX motherboard with SB450 and may be I should wait untill they start offering SB600 on mATX boards. Any suggestions? Thanks Reply
  • Wesley Fink - Thursday, June 01, 2006 - link

    As we understand it, SB600 is not pin-compatible with SB450, so it is not a drop-in for the older chip. We therefore think it is unlikely you should wait for a board redesign on an older 939 board. Any new 939 boards - and there may be some if the market wants them - will likely use SB600. Reply

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