Difference between DDR, DDR2 and DDR3

By Kenza
Oct 22, 2010
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  1. Hi Guys,

    Just a quick question... the differerence between DDR 1,2 and 3.... in terms of pin placement on the motherboard? and am i correct in saying there is no motherboard that supports 2 different types of RAM? also... i wanted to find out the different speeds of RAM eg: 400MHZ,660MHZ 1333MHZ etc.. does that change the compatibility with the motherboard? For example, DDR2 400MHZ is installed can you insert DDR2 800MHZ and it will work? and if so will it work together with the 400 or must you have the same speed with all your RAM?
  2. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 3,435   +145

    There is no reason to post two identical threads.

    DDR1 is 184 pin, while DDR2 and DDR3 are both 240 pin, so some motherboards support both DDR2 and DDR3.
    If the speed is not supported by the motherboard, it will revert to the highest supported speed.
    All RAM will run at the speed of the slowest module. In theory, it should work; I wouldn't count on it.
  3. mailpup

    mailpup TS Special Forces Posts: 6,978   +362

    If I recall correctly, on those motherboards that supported both DDR2 and DDR3 you could only use one or the other at a time.
  4. Route44

    Route44 TechSpot Ambassador Posts: 11,966   +70

    Compatibility also has to do with the voltage the motherboard will run the memory. A few times on these forums people bought certain RAM that was of a particular voltage range only to discover thier motherboard wouldn't run it at said voltage because of design limitations.
  5. captaincranky

    captaincranky TechSpot Addict Posts: 11,668   +1,871

    Newegg has been kicking around this Gigabyte G-41 "Combo" motherboard: It supports both DDR2 & DDR3.

    Please also click on the image link, and you will see that despite both sockets being 240 pins, they have the alignment tab in different places, so you can't put DDR2 into a DDR3 slot, (and vice-versa).

    With that out of the way, I doubt that you can run both types of memory at once. The reviews say no, you can't. Yeah, yeah, yeah, I know about the reviews at the Egg, but I'm going to take their word for it this time.

    I'm sure that this is just a lapse of syntax;
    but it does give the impression that these DDR2 & DDR3 DIMMs are interchangeable with respect to socket type, which isn't so
  6. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 3,435   +145

    Sorry, that's right, the slot's aren't interchangeable, the motherboards just have two pairs of RAM slots.
    Waste IMO because there's little reason to be changing (or even using) DDR2 at this point, aside from reusing to make a really cheap non-performance oriented computer.
  7. Kenza

    Kenza TS Rookie Topic Starter

    ok well thanks guys. sorry for posting it twice. i spelt title terribly so i corrected it. but ideleted the 1st 1.
  8. captaincranky

    captaincranky TechSpot Addict Posts: 11,668   +1,871

    Kenza, you spell everything terribly, but that's OK, we forgive you. :rolleyes:
  9. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 3,435   +145

    If I remember correctly, the first one was spelled right, and the second wrong,
  10. Kenza

    Kenza TS Rookie Topic Starter

    lol well i right in sms talk so half the stuff is in abbreviated form or different form anyway

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