What is DDR433/466/500/533 , DDR has a Max DDR400

Are they overclockable DDR400 modules
According to my knowledge DDR is max 400Mhz with BW3.2GB/s

But at Kingston and Corsair Sites i have seen
DDR433/466/500/533 with BW 3.5/3.7/4.0/4.3 GB/s respectively

Can we use these modules in the motherboard which has a Max DDR400
Eg . ASUS A8N-Sli

Can someone please explain me if these DDR400 and above modules can work in DDR400 supported Motherboards.
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  1. DDR has no official spec above PC-3200, so yes, that is running above spec and thus overclocking...

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    And the sign says "You got to have a membership card to get inside" Huh
    So I got me a pen and paper And I made up my own little sign</pre><p></font color=red>
  2. Memory gets its rating from testing. There was DDR400 before PC3200 officially existed: It took many months (closer to a year as I recall) for JEDEC (the company who sets the standards) to approve PC3200 as an official specification.

    So back then you could say "DDR400 doesn't exist, it's just overclocked DDR333". But after the spec was made, no problem!

    So today we have these modules specifically made for overclocking, DDR433, 466, 500, 533. You could say they were overclocked DDR400, but some of them have used 4ns chips, which are rated for 250MHz in clock cycles (DDR500) to begin with. Still, boards will normally see a DDR500 module as a DDR400 module.

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  3. So will i be able to use it on the ASUS A8N SLi Mobo
    which has support for DDR400/333/266 only.

    Also wanted to ask when i insert DDR400 above modules on
    the Mobo which doesnt support them will they be recognised
    properly as DDR433/466/500/533 or will i have to go to the
    BIOS and change the settings.

    What is this exactly which is written after RAM modules
    For Eg. 2-3-2-5 [4 values] and some even have 2-3-2-6-1[5 values]

    Let use suppose these values as X1-X2-X3-X4-X5
    i know
    X1 - CAS Latency
    X5 - Command Rate [hopefully][not present in the description of all RAM modules i have seen some have this 5th value].
  4. Thanks Crashman

    You exactly have given me the info i had needed.
    So they are DDR 400 Modules but overclockable to DDR433/./533
    By default they are recognised as DDR400.

    So i can use these Modules on a DDR400 Mobo & they will
    be recognised as DDR400 and i will have to overclock it.

    Am i correct.

    I wanted to use these oveclocked modules on the ASUS A8N Sli
    Mobo but it say max DDR400 so i thought i could not use
    DDR400 above modules but after finding out that officially
    DDR400 was the max for DDR 1 i thought how did DDR 433..533
    modules came when DDR400 is Max
  5. Your first paragraph: Are DDR500 modules really DDR500, or are they really just overclocked DDR400 modules. The answer is, BOTH! All modules are capable of running slower than their rated speed.

    And your second paragraph, yes, the board sees them as DDR400 modules. You don't "have to" overclock anything, you can run them fine at 400MHz data rate. But if you want to overclock, the higher rated modules will allow you greater gains in bus speed.

    With the A8N SLi, you can use DDR500 at DDR400 speed, and THEN overclock the entire bus system by 25%. That means the base bus speed will go from 200MHz to 250MHz, the RAM will go from DDR400 to DDR500, and the HyperTransport rate (from the CPU to chipset), well, you'll probably want to drop it from 5x (1000MHz) to 4x (800MHz) so that you'll get back up to 1000MHz when you overclock the bus from 200 to 250 (5x200=4x250).

    <font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
    <font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
  6. Thanks Crashman
    Got it now
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