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    Dual Channel

    Discussion in 'Hardware Components and Aftermarket Upgrades' started by matt_h1, Mar 2, 2006.

  1. matt_h1

    matt_h1 Notebook Deity NBR Reviewer

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    For dual channel ddr2 do both chips need to be the same size? or can I use a 1gb chip and s 256mb chip together and have dual channel.
     
    matt_h1, Mar 2, 2006
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  2. tullnd

    tullnd Notebook Evangelist

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    They need to be the same. Don't worry though...it's not a real big performance bump. It does boost speed, but not a large amount.
     
    tullnd, Mar 2, 2006
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  3. Sofer

    Sofer Newbie

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    Has a good explanation of dual channel.

    I have a 512mb and a 1 GB memory modules (total of 1.5gb) running in dual channel

    On my uniwill 259EN3


    Edit:

    Site didn't post the first time

    http://www.hardwaresecrets.com/printpage/133
     
    Sofer, Mar 3, 2006
    #3
  4. nickspohn

    nickspohn Notebook Virtuoso NBR Reviewer

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    Sofer, Matt -

    You need 2 of the same size RAM to run in Dual Channel mode. There is no other way you can be. If you dont have: 256 x 2, 512 x 2, 1024 x 2; if you dont have that, then your not in Dual Channel.

    There is a guide in the Dummy Guides section all about RAM if you need to know more info. Click here to go there
     
    nickspohn, Mar 3, 2006
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  5. qwester

    qwester Notebook Virtuoso

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    The link you provided says: "In order to use this configuration on your PC, you need to have a motherboard with this feature and two identical memory modules correctly installed (same capacity and same speed – same manufacturer and same model is highly adviced).". Which is true. So how can you be running in dual channel!!!

    What dual channel is by definition, is accessing the 2 modules at once. So for example you have a block of data that is divided into 4 chunks (just an example), so chunk 1&3 will be on module 1, and chunks 2&4 will be on module 2. So now you have access to 2 chunks at a time, while before you could only access one chuck at time. That's what dual channel is. And clearly for this to keep working you need to have identical sized modules (cause otherwise you would run out of space on the smaller one!)
     
    qwester, Mar 3, 2006
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  6. drumfu

    drumfu super modfu

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    i thot the newer motherboards could operate in dual channel without having matching sticks ?
     
    drumfu, Mar 3, 2006
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  7. tullnd

    tullnd Notebook Evangelist

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    They're not as sensitive in timing issues to the chips being the EXACT same(actual physical ram modules on the silicon), but they have to be the same size and obviously operating at the same speed. Previously...having mixed chips was a disaster.

    Along the lines of how you used to have to get processors from the same batch/micro code to run dual. Then with PIII's, you only had to have the same voltage requirements. Even the stepping could be different(provided the older one was installed in Socket 0), just as long as the voltage was the same(since it varies sometimes in steppings).
     
    tullnd, Mar 3, 2006
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  8. drumfu

    drumfu super modfu

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    no, i could have sworn someone posted a screen shot of their system runnin 1 + 256 and operating in dual channel.
     
    drumfu, Mar 4, 2006
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  9. dr_st

    dr_st Notebook Deity

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    Indeed. It was a long time ago too.

    Nowhere in the official specs of Intel's Sonoma platform did it say that the RAM sticks need to be of matching sizes. But people still believe that they do, because this limitation does exist (or has existed) in desktop computers.

    The conclusion that was reached was that the requirement to matching size was a limitation of the chipsets, not something inherently necessary.
     
    dr_st, Mar 5, 2006
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  10. 7toy9

    7toy9 Notebook Enthusiast

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    I bought this kit from Fry's: http://shop3.outpost.com/product/4689938?site=sr:SEARCH:MAIN_RSLT_PG

    It is dual channel. I have it installed, do I need to go into the BIOS to turn dual channel on or does it do it automatically.

    Also, when I run CPU-Z, it shows each stick reading as 332.5mhz or something. Is that because the FSB of the Core Duo is 667mhz? So it effectively reports the max speed used for each RAM chip? Any help appreciated.
     
    7toy9, Mar 5, 2006
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  11. Shampoo

    Shampoo Notebook Deity

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    WOW that's news to me, I didn't know that you could do that on newer boards.

    That's kinda good to know that you can run ram in dual channel without having matching sticks. :D

    Cheers,
    Mike
     
    Shampoo, Mar 5, 2006
    #11