800 MHz vs 667 MHz FB-DIMMs

Article: Harpertown Performance Preview
By: David Kanter (dkanter.delete@this.realworldtech.com), November 14, 2007 12:38 am
Room: Moderated Discussions
gpriatko (nospam@thanksanyway.com) on 11/13/07 wrote:
>Hi David,
>Thanks for the update.
>Yeah, the X7DWN+ looks like a very nice system. I'm about >to order one for SiliconMechanics.com for running sims.
>What's your opinion on the value of 800 MHz vs 667 MHz >memory?

That depends on your app and the working set size. When you say sims, do you mean circuit sims?

Generally, increasing the FSB speed while keeping memory speed constant is nice, but isn't a huge win. You always want a nice ratio between FSB and memory, otherwise it adds a variable latency to memory requests.

>I'm having trouble finding 800 MHz FB-DIMMs. Supermicro >says that they've tested
>the Kingston 1GB modules in the X7DWN+. They also claim to >have tested 2GB and 4GB
>modules in the X7DWA-N. I can't find those modules on the >vendor's web sites.

Interesting. That's one of the downsides of doing reviews where you receive the system - it gives you no information on availability, since we receive seed systems, like what are provided to key ISVs.

>I suspect that the reason that there are no 2GB or 4GB >modules validated for the
>X7DWN+ is caused by some limit with the number of ranks >that the memory controller can keep active.

That's possible.

>The X7DWA-N has fewer DIMM slots than the X7DWN+. If the >2GB and 4GB modules are
>using lots of ranks, then that could be why there are no >2GB or 4GB modules for the X7DWN+.

Yea, I'm not really sure.

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TopicPosted ByDate
Harpertown Preview OnlineDavid Kanter2007/11/09 06:44 AM
  Stoakley vs. BensleyAnonymous12007/11/09 08:58 AM
  Harpertown Preview OnlineMarcin Niewiadomski2007/11/09 11:59 AM
    Harpertown Preview OnlineDavid Kanter2007/11/09 06:51 PM
      So...anonymous2007/11/09 07:47 PM
        So...anon2007/11/09 08:49 PM
          So...anonymous2007/11/09 09:25 PM
            So...anon2007/11/09 10:50 PM
              That's just how I writeDavid Kanter2007/11/10 12:44 PM
                That's just how I writeanonymous2007/11/10 04:58 PM
                  That's just how I writeDean Kent2007/11/10 07:27 PM
                    ;-)anonymous2007/11/10 07:31 PM
      Harpertown Preview Onlineanonymous2007/11/09 11:10 PM
        Harpertown Preview OnlineDavid Kanter2007/11/10 01:49 PM
      Harpertown Preview OnlineMarcin Niewiadomski2007/11/10 03:10 AM
        Harpertown Preview OnlineMarcin Dalecki2007/11/11 04:01 AM
          Harpertown Preview OnlineJoe Chang2007/11/11 09:56 AM
            Harpertown Preview OnlineJoe Chang2007/11/11 06:15 PM
  xmlmark and jbbHenrik S2007/11/09 12:30 PM
    alsoHenrik S2007/11/09 12:43 PM
      alsoDavid Kanter2007/11/09 06:52 PM
        alsoHenrik S2007/11/10 12:09 AM
  Harpertown Preview Online*(&^2007/11/09 11:38 PM
    Harpertown Preview OnlineDavid Kanter2007/11/10 01:53 PM
  Supermicro MBgpriatko2007/11/11 12:48 PM
    Supermicro MBgpriatko2007/11/12 01:48 PM
      Supermicro MBDavid Kanter2007/11/13 12:52 AM
        800 MHz vs 667 MHz FB-DIMMsgpriatko2007/11/13 08:09 PM
          800 MHz vs 667 MHz FB-DIMMsDavid Kanter2007/11/14 12:38 AM
            800 MHz vs 667 MHz FB-DIMMsgpriatko2007/11/15 08:29 PM
  New O-O-O transaction Mode?blaine2007/11/12 05:37 PM
    New O-O-O transaction Mode?Andi Kleen2007/11/12 05:57 PM
      New O-O-O transaction Mode?Michael S2007/11/13 01:45 AM
    New O-O-O transaction Mode?Michael S2007/11/13 02:05 AM
    New O-O-O transaction Mode?David Kanter2007/11/13 03:46 AM
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