Understanding Atom: Three Models for the Same CPU

Let me clear up some naming confusing regarding Atom. While there’s only one Atom processor, it comes in two different versions: Silverthorne and Diamondville. Silverthorne is the version intended for use in MIDs (Mobile Internet Devices), it’s a part of the Z5xx series. Diamondville is the version intended for desktops, notebooks and netbooks - it’s the N2xx, 2xx and 3xx series. The N2xx is used for netbooks, while the 2xx and 3xx are used for desktops. The 3xx is a dual core version of Diamondville. The 2xx and 3xx chips simply draw more power than the N2xx. They also support 64-bit instructions, while the rest of the lineup is 32-bit only.

That's Atom, in case you've forgotten

Performance between Silverthorne and Diamondville at the same clock speed is identical. Silverthorne uses a CMOS bus interface instead of a GTL FSB, which consumes less power but also means that it won’t work with conventional desktop chipsets. Silverthorne is thus paired with Intel’s Poulsbo chipset (sold under the UL11/US15 chipset name).

Diamondville supports the standard GTL FSB interface, and will thus work with desktop Intel chipsets. This version won’t work with Poulsbo, but will work with 945G as well as NVIDIA’s GeForce 9400M. Anything that can work with a Core 2 or Pentium 4 processor should be able to work with Diamondville.

Both versions are sold under the Atom name, they simply carry different model numbers. I’ve summarized everything in the table below:

  # of Cores/Threads Clock Speed/L2 FSB 64-bit Target Market TDP Price
Intel Atom 330 2/4 1.6GHz / 512KBx2 533MHz GTL+ Y Desktops/Notebooks 8.0W $43
Intel Atom 230 1/2 1.6GHz / 512KB 533MHz GTL+ Y Desktops/Notebooks 4.0W $29
Intel Atom N270 1/2 1.6GHz / 512KB 533MHz GTL+ N Netbooks 2.5W $44
Intel Atom Z540 1/2 1.86GHz / 512KB 533MHz CMOS N MIDs 2.4W
2.6W w/ HT
Intel Atom Z530 1/2 1.60GHz / 512KB 533MHz CMOS N MIDs 2.0W
2.2W w/ HT
Intel Atom Z520 1/2 1.33GHz / 512KB 533MHz CMOS N MIDs 2.0W / 2.2W w/ HT $40
Intel Atom Z510 1/1 1.1GHz / 512KB 400MHz CMOS N MIDs 2.0W $20
Intel Atom Z500 1/1 800MHz / 512KB 400MHz CMOS N MIDs 0.65W $20


I had to get that out of the way because some manufacturers are opting to go with Silverthorne for their notebooks, while others are using Diamondville. And the model numbers are different enough to be confusing, despite fundamentally being the same processor. Just to reiterate, an Intel Atom Z530 offers the same performance as an Intel Atom N270, they both work at 1.60GHz.

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  • Roland00 - Tuesday, January 13, 2009 - link

    The asus you are referring to is using the discrete version of the chip. It isn't built into the motherboard like the ion. Doing so saves cost, space, and to some extent heat and battery life.
  • mmntech - Monday, January 12, 2009 - link

    You're thinking of antitrust/competition law. Fair Use deals with copyright.

    All I can say is the 9400M is a pretty decent GPU for the low power market. It scores about 2000 3DMarks on the MacBook, which is vary respectable for an IGP. Intel's GMAs are pretty much useless these days, especially the 950. This might force them to innovate their platform.
  • yyrkoon - Tuesday, January 13, 2009 - link

    Yes, thanks antitrust/competition laws are what I was thinking, just could not think of the correct term.

    Low powered decent graphics are exactly what I am personally looking for. Something to play most older titles decently, and not draw 5 Mw just to use the darned things. I have an Intel core 2 duo system with a NV 9600GT in it, and while playing WiC it does a great job, but at the cost of like 230W. Since we're solar now, this will not work of course, and I do not expect to play WiC on an atom system, but at least some older, or less demanding games.
  • has407 - Monday, January 12, 2009 - link

    Yet the Z5xx (except Z500/Z510) supports VT but Diamondville doesn't? Why would anyone want VT on a MID vs. a netbook/desktop? Would be interesting to hear Intel's rational for the feature mix--silicon/power constrained, or marketing, or simply because they could with little or no penalty? Or does Intel expect VT in the MID market to be important? Or maybe not a MID but maybe a 24x7 very low power home gateway/management/virtual-appliance server? (Been on my wish list for a long time, and why VT support or its equivalent is of interest.)
  • Fanfoot - Monday, January 12, 2009 - link

    While the Z and N series Atom's may be comparable, as you say the buses are different, so they require different support chips. As far as I know this means that with a Z-series Atom, you are stuck with the Poulsbo chipset. Which means that with the Z-series Atom's you implicitly take on the limitations of Poulsbo.

    Could you clarify what the limitations of Poulsbo might be? Like for example is it still limited to 1GB of RAM? What about the advantages, like the supposed video acceleration and power savings. Have you done any testing that suggests these claims are in fact valid?

    For example, Dell has chosen to use the Z530 in their upcoming Mini 10 model, and I wonder what the advantages/disadvantages might be wrt the Dell Mini 9? Will that 3 cell battery last longer? Will it handle 1080i video playback better (at all) than the Mini 9? Will there be a RAM slot on the back like with the Mini 9? Does a manufacturer have to use Poulsbo to offer HDMI support? What about SATA drives?
  • has407 - Tuesday, January 13, 2009 - link

    FWIW... Based on the Intel datasheet, Poulsbo is limited to 1GB (1.8V X 2 or 1.5V X 1, 512Mb or 1025Mb devices), but whether those are silicon or marketing limits is unknown. The part TDP is 2.3W, and Intel shows a system TDP (w/Z500) of 2.95W, which bodes well but obviously assumes the lowest power Z500. Even with that, we might see a solution come in at 20-25W. Whether that provides adequate video performance is more difficult to interpret... both H.264 and VC1 appear to be supported at 1080i/30fps. However, what that means in the real world will likely have to wait until we see hands-on testing. (Of note, the datasheet specifically does *not* mention support for VC1/L4, so those looking for 1080p/30 for all HD may need to look elsewhere... unless the CPU can help make up the difference.) Obviously, some real-world/hands-on testing will be required before a verdict is in.
  • Mr Perfect - Tuesday, January 13, 2009 - link

    Poulsbro is no longer limited to 1GB, it is now capable of 2GB.

    They changed the spec and announced it in an update sheet.

    You can check it out by going to Intel's site, finding the "Intel® System Controller Hub US15W" page, and then going to the "Technical Documents" section. The "Intel® System Controller Hub (Intel® SCH) Specification Update" PDF details the change.

  • has407 - Wednesday, January 14, 2009 - link

    Thanks for the update (reminder to self: check before posting :)
  • Khato - Tuesday, January 13, 2009 - link

    Well, the real question on the 1GB limitation is whether it's silicon or packaging. The motivation for it was most likely packaging/target market segment, but due to the targeted design of the chip I wouldn't be surprised if that resulted in cutting any extra address logic from the design. Is 1GB really an issue? No way, so long as you're running a reasonable OS on it.

    As for the media performance of Poulsbo - http://www.anandtech.com/tradeshows/showdoc.aspx?i...">http://www.anandtech.com/tradeshows/showdoc.aspx?i...

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