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 ATI's Rx480 and RD580 for Socket 939 were somewhat hampered by the outdated feature set of their SB400/SB450 Southbridges.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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  • lopri - Thursday, June 01, 2006 - link

    Most of responses below my post didn't read my points. I'll be paitently waiting for AT staff's responses. In the meantime, you guys can check:">">

    And the sub-reviews. If DDR400(2-2-2) are DDR600(2.5-3-3), I guess all those memory reviews on AT were wasting of time?

    Ahe here is the DIMM sticks this review used for AM2 platform.">

    Oh that's not it. While searching, I found that decent DDR2-800 would cost >$250, and higher speed/same timing or same speed/timing sticks will (if you were to buy) dig a big hole in your packet. (think $500) Is that mainstream? What about the 1T issue??

    The top of the line Socket 939 vs Socket AM2 comparison could be something like this:

    2 x 512MB: DDR600 with 2.5-3-3-7 (less thanl $150) vs DDR2-800 with 3-3-3 ($500) or,
    2 x 1GB: DDR500 with 2.5-3-2-7 (less than $200) vs DDR200-800 with 4-4-4 ($250)

    Think about how mwny mobo/memory reviews we've seen here on AT? Why don't we use the knowledge we learned from those founding to compare Socket 939 and Socket AM2?

  • Spoelie - Thursday, June 01, 2006 - link

    You need a reality check. Lots of reviews have pointed out that the higher cost of TCCD memory and such is not worth the little extra performance, except if you're a serious overclocker that just really wants to run his mem on 1:1 and need the frequency headroom.

    The common setup out there is not 270-2.5/3/2 or whatever, it is 200-2.5/3/3/8 or even CL3. Especially with the higher density memories like 1GB sticks. THAT is what most persons are running. If anything, the 2/2/2 200 are a bit too high end for the majority of people. And they're also reading AT.
  • lopri - Thursday, June 01, 2006 - link

    What you're saying is not totally out of my context. My main meat was towards the reviewers. Does anyone here own a DDR2-800/3-3-3? (Forget about TCCD 270MHz) DO you know how much they are? Indeed, such memory is not even officially out yet. But AT is using those sticks for AM2 system but at the same time for Socket 939 system they use more "pedestrian" DDR400/2-2-2. These days you can by 2 x 1GB DDR400/2-3-2 for under $200.

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

    The Corsair 8500 we used for testing is NOT rated at DDR2-800 3-3-3 - it is actually rated at DDR2-1066 5-5-5-15. The fact is it will run at DDR2-800 3-3-3 with voltage in the 2.1 to 2.2v range. So will most other recent dimms based on Micron memory chips. At stock voltage of 1.8v it runs about 4-4-4-13.

    Where TCCD was capable of DDR400 2-2-2 and DDR500 2.5-2-3 or 2.5-3-3, Micron chips are currently the top-performing chips for DDR2. Infineon also has DDR2 chips that perform at lower latency and they are generally priced more reasonably.

    Our memory articles ALWAYS compare performance at different memory speeds, but 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, though there will likely be a DDR2-1066 speed in the near future.

    When we point out that the massive bandwidth increases in DDR2 on AM2 have almost no impact on performance, surely it is obvious that AM2 is not memory bandwidth starved. We found on DDR that the on-chip memory controller for AMD was very sensitive to latency improvements. In fact hte mad shrimp article unintentionally shows just that - gaming responded more to latency improvement than bandwidth improvement. That will also likely be the case in DDR2 EXCEPT with such a massive increase in bandwidth over DDR, latency may not matter nearly so much. We will take a closer look at htis in a future memory article.
  • peternelson - Thursday, June 01, 2006 - link

    Price of fast, low latency DDR2 will come down once AMD users start buying it in volume. That will come, so it is not unrealistic to benchmark now using fast expensive highend memory, because it won't be as expensive or uncommon in a month or two or three when boards are in most stores and consumers are buying them in bulk eg for "back to school/college" or "Christmas holidays season" which are when sales peak. Conroe should also improve the market availability for high performance DDR2 memory.

    On the other hand there are reports of far east short-term wholesale prices of ddr2 generally having a rise because of more demand.
  • Spoelie - Thursday, June 01, 2006 - link"> Reply
  • peternelson - Thursday, June 01, 2006 - link

    AMD are moving to AM2 with or without you.

    Get over it.

    You will not be able to get AMD's top performing new models if you stay with 939. Ditto the 65nm processors will also be on AM2.

    939 WILL be phased out sooner or later, and with it goes DDR support.

    Therefore it is somewhat irrelevant question to complain about the speed of the DDR. There won't BE any DDR support going forwards. Make the transition.
  • lopri - Thursday, June 01, 2006 - link

    Did you even read my post? What was I saying?
    It has nothing to do with AM2 transition and I have nothing against AM2.
  • peternelson - Thursday, June 01, 2006 - link

    Yes, the ddr comments relate to your Q1 section, not the DDR2 discussion.

    Sorry if my response seemed overly critical.
  • lopri - Thursday, June 01, 2006 - link

    On page 3, in the table

    PCIe Speeds | 100 to 2000 in 1MHz Increments

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