Sandra Bandwidth Test

Discussion in 'Abit' started by Joe Murphy, Mar 13, 2005.

  1. Joe Murphy

    Joe Murphy Guest

    I have an IT7 w/845E chipset. When I run the Sandra memory test I see an
    efficiency of 42%. I have a:
    p4 3.06GHz OC to 150MHz
    1 Gig PC2700 DDR - 300 Mhz

    Can anyone explain why the efficiency is so low? My other PC running is 85%
    (ECS junk board with p4-2GHz/PC2700 Memory)

    joe
     
    Joe Murphy, Mar 13, 2005
    #1
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  2. Joe Murphy

    rj Guest

    you answered your own ? i think.if you say it is at 150 fsb,ddr
    300,that means you are running a 1-1 divider.go into the bios,and set
    the divider to 3-4.
    but then your pc2700 ram will be running way out of spec at
    ddr400-pc3200
    150 fsb divided by 3 x4 =200fsb on the ram
     
    rj, Mar 13, 2005
    #2
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  3. What version of Sandra, and what are the actual figures?
    Have you manually set the 1:1 FSB to memory divider, or have you allowed the
    board to set the memory bus speed automatically?
    We can't explain with 100% authority, no, as we don't have your PC in front
    of us to reproduce the tests and check your settings. The best we can manage
    in the circumstances will be educated guesses, and even there we really need
    some more information.

    What happens to the memory bandwidth figures if you clock the PC back down
    to default speed? Does the bandwidth efficiency alter to any significant
    degree?
    Is it overclocked? Is it a single or dual channel board? What are the actual
    bandwidth figures it reports?
    --


    Richard Hopkins
    Cardiff, Wales, United Kingdom
    (replace nospam with pipex in reply address)

    The UK's leading technology reseller www.dabs.com
     
    Richard Hopkins, Mar 13, 2005
    #3
  4. Joe Murphy

    Spajky Guest

    for "Real Life" memory performance efficiency to compare with others
    see mx site under comp/benchmarks, link @ "updated" ...
     
    Spajky, Mar 13, 2005
    #4
  5. Joe Murphy

    Joe Murphy Guest

    Latest LITE Version
    2180 MBITS/sec
    YES manualy set to 1:1
    Efficiency Improves very slightly at Ck=133MHz
    Not overclocked with DDR266 frequency single channel memory
    Reports 2040MBITS/Sec.

    I thought that that it was posible that I was causing a degradation that
    would be obvious to an experienced user. For instance, operating the memory
    at a frequency out of sync with the CPU (If that makes any difference&).
    Joe
     
    Joe Murphy, Mar 13, 2005
    #5
  6. Joe Murphy

    Dazzer Guest

    My experance is that some chipsets don't give good bandwidth,

    My last KT400 chipset was similar (single channel), although the NF4 Ultra I
    have now gives 92% @ 6.02Gbits (dual channel), both with the same 512MB
    PC3200 memory sticks.

    Dazzer
     
    Dazzer, Mar 21, 2005
    #6
  7. Joe Murphy

    Spajky Guest

    thats true, but it is not all in the bandwidth ...
    (DDR has double that than SDRAM, but using same real clock frequencies
    & latencies, the second is faster in real life (& using WinRAR3.3
    benchmark & hardware test under Tools tab, DDR2 is even slower than
    DDR1 ...)

    Sandra has some good subtests for "real life" benchmarking & comparing
    (depends also on revision of it) like drive index for HD performance
    and other useless ones like max.mem.bandwith test (but good for
    marketing purposes). The last is almost useless for "real life" IMHO,
    since practically almost never the transfers between mem. controller
    reach its peak speeds ...

    time to time I have access (repairing stuff too) to different
    platforms so I checked also DDR based sistem with same real CPU
    clocks/FSB/memClocks & same peripherals with SAME OS install (minimum)
    between my setup and I can tell you that mine is faster in average
    work (you can feel it & bench it with stop watch too). The major
    difference between these platforms was just a WinRar mem Score !

    Even thru Sandra mem bench showed much better performance for an AMD
    platform of the time (AMD XP1500+ for example), my setup was faster -
    noticeable (more than 10%); WinRar mem score was almost 50% higher on
    mine! IMHO WinRar developers made a hell of a memory benchmark, but
    is not accepted yet in the "benchmark" comunity since that uses widely
    established Sandra results, but does not understand fully certain
    stuff, because people have been bombarded with marketing blurb for
    years & not tried to brainstorm with a bit of distance away from that
    "widwly accepted thruths" ...
     
    Spajky, Mar 21, 2005
    #7
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