Have Q9550 & DDR2-800, which motherboard?

Discussion in 'Gigabyte' started by John Doe, Feb 21, 2010.

  1. John Doe

    John Doe Guest

    Which Gigabyte motherboard would you buy if you had a Q9550, four 1GB
    modules of DDR2-800, and a GeForce 7950GT/500, and an SSD main drive?

    Would you ditch the DDR2 memory and go for a GA-EP43T-UD3L and buy
    DDR3-1600 memory modules?

    I play Forged Alliance and the upcoming Supreme Commander 2, and do
    some flight simulation FS 9/10.

    John Doe, Feb 21, 2010
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  2. John Doe

    Paul Guest

    You can buy DDR3-1600 memory modules if you want, but you should look at their
    tested memory table first. The DDR3-1600 entries are all single sided
    modules. I don't know if they did that, so they could tick all the
    columns in the table ? Or whether they really tried 2x2GB DS modules
    (one stick per channel) and it didn't work ? In any case, the implication is,
    that operation at DDR3-1600 is near the limits.


    As for memory speed and its effect on performance, the bottom table here
    gives a small sampling. From DDR3-800 CAS5 to DDR3-1600 CAS6, the
    benchmark time goes from 40.95 seconds to 39.16 seconds. That is a
    4.6% difference caused by the memory alone (as they're tweaking FSB
    and multiplier for constant core speed).


    So while you asked about DDR2 versus DDR3, the results in that
    table should give you some idea what changing the memory would do.
    DDR3-800 CAS5 is industry standard, and isn't even an enthusiast
    memory. While DDR3-1600 CAS6 is bleeding edge, and it was the lowest
    CAS I cound find on Newegg for that memory.

    Memory has both latency and frequency as a consideration. Low latency
    memory could add a bit to the purchase price, and it is a factor too.
    So when you ask about DDR3-1600, is it CAS6 or CAS9 ? CAS6 would be

    In addition to the basics, as shown in that Anandtech article, there
    is another article here. This discusses tuning and the difference a
    good BIOS can make. The GA-EP43T-UD3L board does have a BIOS
    page with tRD in it. And the "(G)MCH Frequency Latch" appears to
    be support for setting the "strap".


    I can't even tell you, looking at that article, what you should
    buy now. Using the Auto settings, the BIOS will set tRD according
    to whatever memory you install, so you don't actually have to do
    any math to use the motherboard. The main purpose of that Anandtech
    article, is if you wanted a math basis for making a selection.

    The lowest latency DDR3-1600 memory I could find, was CAS6.
    It meets those specs, at 1.65V (nominal is 1.5V), so the RAM
    doesn't need to be punished to do well. 2x2GB $170. A faster
    memory should be able to run at a slower speed, if the DDR3-1333
    setting is needed.


    The fastest memory you can get now, is this DDR3-2400 CAS9. The latency,
    when scaled for frequency, is the same as the previous product (at
    DDR3-1600 it would run CAS6). The interesting question, is what computer
    a memory like that would make sense on ? What FSB and dividers would you
    need to hit that speed ? Another cute aspect of this product, is
    it comes with its own cooling fan. I wonder how long that'll last.


    Paul, Feb 21, 2010
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  3. John Doe

    Fishface Guest

    That particular benchmark is very dependent upon memory bandwidth.
    In your average real world application it probably matters not as much.

    Recently, I swapped two 1GB sticks of DDR2-667 for the one 2GB stick of
    DDR2-800 I had put in my mom's computer. The SuperPi Mod 1M time
    increased by nearly ten seconds! Apparently the old memory had been
    running asynchronously at 400 MHz and I set the new stuff for just 200 MHz,
    which was synchronous for this CPU (E2200). When I set it to run at 333 and
    lowered the CAS latency, most of the performance came back. I never
    imagined it would matter that much. This is on a single channel ECS board
    (671T-M) with a SIS chipset that came essentially free with my Q6600 at Fry's.
    Fishface, Feb 22, 2010
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