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 ATI's Rx480 and RD580 for Socket 939 were somewhat hampered by the outdated feature set of their SB400/SB450 Southbridges.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.

ATI SB600
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  • Stele - Friday, June 02, 2006 - link

    Odd that the board uses two 3132s to provide the extra 4 ports - probably for logistic and pricing reasons (easier to stock and better economy of scale when buying 2x one chip compared to 2 different chips).

    I say it's 'odd' because the 3132 was specifically designed to work with port multipliers, specifically their SiI 3726 1-to-5 drive multiplier. The 3132 thus has only 2 ports to save space and costs (for customers who only need 2, e.g. laptops). In this motherboard's case, instead of having two 3132s giving 4 ports, you could use one 3132 and one 3726 to provide (1 + 5 =) 6 extra SATA ports via the 3132, bringing the total number of SATA ports on the motherboard to 10.

    Indeed, this would probably be a useful combination: 4 from the SB600, 4/5 from the 3726 and the remaining 1/2 routed to the back as eSATA. For routing simplicity, I suspect board designers may keep all the ports from the 3726 in one cluster near the IC and hence as internal SATA, leaving the 3132's other channel available for eSATA.

    While we're on the SATA question, I'd like to ask if anyone has any confirmation about the RAID levels supported by the SB600. This is because on pg 2 of the AT review, it mentions in the diagram that SB600 supports, inter alia, RAID 5. However, on pg 3, the table does not list RAID 5 among the supported RAID levels.

    I then went to ATi's website to check out their own pages on the SB600. Interestingly enough, there was the same problem - the diagram was also there, showing RAID 5, but their own spec sheet does not mention RAID 5 either! So does the SB600 support RAID 5 or doesn't it? :P
    Reply
  • Chadder007 - Thursday, June 01, 2006 - link

    I wish ATI and NVidia would get off of this Dual Card setup crap and get their act together and make a Single Dual Core video card, in the way Dual Core Processors are being made now. Reply
  • Trisped - Thursday, June 01, 2006 - link

    That would be nice, but the power drain and heat dissipation problems would be un real. Then people would still want a dual card solution. I can see it now, you need a 1K power supply for your video cards and one for the rest of your system. Your video cards take up 6 slots and have fans that sound like a 1960s sports car. Your CPU has 4 cores and everything is over clocked 25-50%. Reply
  • JarredWalton - Thursday, June 01, 2006 - link

    There have actually been several dual GPU cards released in the past, although all of them still require SLI motherboards in order to function. (The SLI requirement is due to NVIDIA's drivers requiring an SLI chipset in order to function.) As far as making dual core GPU -- like the Pentium D, Athlon X2, Core Duo, etc. -- there's actually no point in doing so. Graphics functions are essentially infinitely parallel, so rather than making a dual core G70, they could just make a 48/16/32 (pixel pipelines/vertex pipelines/ROPs) chip instead. Of course, that would require something like 600 million transistors, so until we start getting GPUs made on 65 nm aren't likely to see such a design (or anything close to it). Reply
  • peternelson - Thursday, June 01, 2006 - link


    On MAJOR difference not covered is in useable PCIE lanes.

    The review talks about

    x16 graphics
    x16 graphics
    no useable pci remain on the reference board
    1x pcie
    1x pcie

    whereas the nvidia 590 solution offers much more including pcix4.
    This is important for people who want to stick in extra raid controllers or specialist cards.

    It would be good to highlight this shortcoming and whether it is purely down to the reference motherboard design or to the chipset not supporting as many lanes as the 590.

    Also you mention that nvidia are working on putting both x16 in some future northbride (which will be nice). Can you give any hints as to timing, naming, or if this will be dubbed "nforce 6"
    Reply
  • Wesley Fink - Thursday, June 01, 2006 - link

    We are expecting a bit more information and we will then add this to our comparison chart.

    ATI RD580 AM2 has 40 PCIe Lanes - 32 for 2 x16 slots, 4 for interconnect between North and South bridge and 4 available for x1 x2, x4 slot(s). In addition the SB600 supports 6 PCI slots.

    nVidia has 46 PCIe lanes available with 9 links.
    Reply
  • psychobriggsy - Thursday, June 01, 2006 - link

    This review says there is GigE in SB600, with a PCIe attached PHY.

    It also says that nVidia's dual GigE is via PCIe attached PHYs. PHYs do not connect via PCIe, they connect to a GigE controller (whereever it is located).

    In the case of nVidia, the southbridge has two GigE controllers integrated. In the case of SB600, there is no GigE controller, you attach it via PCIe x1, allowing you to use decent controllers, or crappy realtek controllers (making motherboard purchases have another thing to check).
    Reply
  • Stele - Friday, June 02, 2006 - link

    quote:

    allowing you to use decent controllers, or crappy realtek controllers


    That's probably what ATi's thinking. There are pros and cons to both nVidia's ondie MAC and SB5600's lack of ondie MAC. By having no controller on the SB600, the chip cost is reduced while motherboard manufacturers have complete freedom to choose whichever controller they would like to include - Marvell, Realtek, etc. and single- or dual-port.

    The only downside is that you'd need extra real-estate on the motherboard, though arguably it's not that big a deal, especially if controllers with built-in MAC and PHY are used. After all, for dual-port networking capabilities that has server-like features like teaming and fail-over, manufacturers can just use such products as the very attractive Marvell 88E8062 PCIe x4 dual-port GbE controller - which some motherboards like the Asus P5WDG2-WS already do.

    Indeed, I'm hoping (dreaming?) that at least one of the top motherboard brands would use this controller in their RD580 solutions, but the fact that the controller is likely going to be quite expensive, along with the perceived lack of the need for such a high-end component would probably kill that idea.
    Reply
  • Wesley Fink - Thursday, June 01, 2006 - link

    BOTH the ATI and nForce 590 use PHYs that connect to the chip and communicate over a PCIe lane. We were merely differentiating that the Gigabit LAN in both cases communicated over PCIe and was not connected to PCI. nVidia has 2 Gigabit PHY connections, while ATI has 1 Gigabit PHY connection. Reply
  • peternelson - Thursday, June 01, 2006 - link

    He's right, the PHY (external or internal) connects to the MAC, which is subsequently connected to the pcie lanes. No pcie goes to any Gbe PHY. Reply

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