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    RAM Bandwidth

    Discussion in 'Dell' started by me_ram, Apr 21, 2008.

  1. me_ram

    me_ram Notebook Geek

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    I ordered 4GB DDR2 RAM @ 667MHz (2 Dimm) for my XPS M1330. But when I look through CPU-Z, I find that the max bandwidth is listed as PC2-5300 (333 MHz). Manufacturer - Hyundai.

    Is is supposed to be like this? :confused: :confused: I thought that both of them would be 667 MHz each.


    [​IMG]

    [​IMG]

    Can anyone please explain this?
     

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    me_ram, Apr 21, 2008
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  2. miner

    miner Notebook Nobel Laureate

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    Yeah, its normal. Its DDR(double data rate) memory and the manufacturers list & market the effective clock rates.
     
    miner, Apr 21, 2008
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  3. me_ram

    me_ram Notebook Geek

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    Sorry If I sound childish.... But, how would 333 be the maximum bandwidth if the effective clock rate can be more? :mad:

    And if it is of any use, this is what I have in my invoice...

     
    me_ram, Apr 21, 2008
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  4. nizzy1115

    nizzy1115 Notebook Prophet

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    If they were 667 each and running in dual channel then it would be 1334 mhz ram :-O

    When running in dual channel the memory is cut in half but multiplied x2 (effective) so in the end it is 667. You didn't get screwed on the sale. Everything is fine.
     
    nizzy1115, Apr 21, 2008
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  5. Lithus

    Lithus NBR Janitor

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    No. Dual Channel != Double Data Rate.

    Double Data rate is synonymous with processors having a multiplier. 333 x 2 = 667. Both sticks are running at 667 each.

    Dual Channel is both running "together", having a maximum rate of 1333, however, due to chipset limitations, the maximum speed is limited at 800. I don't know if CPU-Z allows you to check this.
     
    Lithus, Apr 21, 2008
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  6. miner

    miner Notebook Nobel Laureate

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    Nothing to do with dual channel.

    Ok, this is a bit tricky to explain but here's the watered down version(search the web if you want a full technical explanation)...manufacturers figured out a away to transfer data twice per clock cycle. So, effectively they doubled the amount of data transfers at the same clock speed, so for example a DDR memory running at 100MHz was capable of effective transfer rates of a single data rate memory running at 200Mhz. This has always been the case since the introduction of DDR RAM, nthing special and no you havent been cheated out of faster memory or anything like that.
     
    miner, Apr 21, 2008
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  7. nizzy1115

    nizzy1115 Notebook Prophet

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    eh meant to say double data rate...my bad
     
    nizzy1115, Apr 21, 2008
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  8. Sparky 1720

    Sparky 1720 Notebook Consultant

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    The way they figured out to do it was they used to only transfer on the peak spike of one side of the voltage pulse, they doubled it by using both sides of the wave.... I just wonder who thought the original method was a good idea?
     
    Sparky 1720, Apr 21, 2008
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  9. me_ram

    me_ram Notebook Geek

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    nizzy1115, Lithus, miner, Sparky 1720 - Thanks for all the info! :)

    Although you had different opinions, the bottom line is that my RAM is okay. This is good enough! :cool:
     
    me_ram, Apr 22, 2008
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  10. bubbatex

    bubbatex Notebook Deity

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    I love this forum - I just loaded some 2gb Crucial PC5300 DDR2 in my Sony and decided to try CPU-Z. I saw 333 MHz and started to flip - making sure the part number I bought was what I got. Than a quick search here explains it...... Thanks from bubbatex too!
     
    bubbatex, May 5, 2008
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