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    Laptop memory - dual channel not working

    Discussion in 'Hardware Components and Aftermarket Upgrades' started by akurei, Feb 20, 2007.

  1. akurei

    akurei Newbie

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    Hi, i recently upgraded my PackardBell EASYNOTE MZ35-26 to 1gb Ram using 3rd party memory. Both the original and the new ram are matched in terms of speed/parity etc, and in CPU-z they show exactly the same properties.

    The problem i'm having is that they are showing as operating only in single channel mode, not dual cahnnel as i'm led to believe they should be.

    The Bios shows as only having 896MB of ram fitted - this is because of the integrated 128 mb graphics on the mainboard. 896+128 = 1024

    could this be the reason that they do not work in dual channel mode? and if so, is there any way to set dual channel before the memory is allocated to the video card?

    any help would be appreciated.
     
    akurei, Feb 20, 2007
    #1
  2. NetBrakr

    NetBrakr Notebook Deity

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    Hello, and welcome.

    If you get dual channel working, you will not get a noticable performance increase, just a tad.

    JC
     
    NetBrakr, Feb 20, 2007
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  3. moon angel

    moon angel Notebook Virtuoso NBR Reviewer

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    I believe dual channel needs not only the same specs but the exact same ram chips to work, i.e. two identical chips of the same manufacturer and same model etc. but I could be wrong about that.
     
    moon angel, Feb 20, 2007
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  4. John Ratsey

    John Ratsey Moderately inquisitive Super Moderator

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    I have never been convinced about this dual channel theory. I have two notebooks (see signature).

    The X60plus now has 1GB is Transcend DDR2-4200 (533) and 1GB Corsair DDR2-5300 (667). Both run at the speed of the slower module. CPU-Z reports the timing as 4-4-4-12-16 at 266MHz. The first 4 is the CAS# latency. CPU-Z also tells me that the memory is dual channel.

    The Q35 has 1.25GB RAM (1GB Samsung module + 256MB on the motherboard). CPU-Z reports the timing as 4-4-4-11-16 at 266MHz. CPU-Z also reports this RAM as being dual channel. Go figure!

    I asked Sandra for her opinion using her memory bandwidth benchmark. The X60's RAM returned 3324/3337 MB/s (admittedly after a reboot - it was nearer 2000 before the reboot perhaps because RAM suffers fragmentation after a dose of hard work). In comparison, the Q35's RAM scored 3149/3157 MB/s.

    I don't know whether that performance difference is due to (i) the X60 is actually running dual channel but the Q35 is not; or the CPU has an impact on memory performance (Sandra's reference results include the CPU); or the integrated graphics on the Q35 reduce the available RAM bandwidth. What I do know is that the benchmark test results are quite variable and anything between about 2500 and 3500 MB/s is typical for a current notebook.

    John
     
    John Ratsey, Feb 20, 2007
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