STREAM results: DDR versus SDRAM

From: Rui Pedro Mendes Salgueiro (rps@mat.uc.pt)
Date: Fri Jul 13 2001 - 13:18:59 CDT

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    I had here temporarily a PC with:

    AMD 1.333GHz /266 MHz in an Asus A7M266 mb with 256 MB of 266 MHz DDR RAM
    SUSE Linux 7.2 ( gcc version 2.95.3 20010315 )

    I also have a

    Athlon 1.3 Ghz/200 Mhz in a Gigabyte 7ZX mb with 256 MB of 133 MHz SDRAM
    SUSE Linux 7.1 ( gcc version 2.95.2 19991024 (release) )

    I compared these two using the STREAM benchmark (compiled with gcc -O)
     * Program: Stream
     * Programmer: Joe R. Zagar
     * Revision: 4.0-BETA, October 24, 1995
     * Original code developed by John D. McCalpin

    Array size = 8000000, Offset = 0
    Total memory required = 183.1 MB.
    Each test is run 10 times, but only
    the *best* time for each is used.

    Results:

    SDRAM
    -------------------------------------------------------------
    Your clock granularity/precision appears to be 9999 microseconds.
    Each test below will take on the order of 259999 microseconds.
       (= 26 clock ticks)
    -------------------------------------------------------------
    Function Rate (MB/s) RMS time Min time Max time
    Copy: 474.0741 0.2770 0.2700 0.2800
    Scale: 474.0741 0.2700 0.2700 0.2700
    Add: 600.0000 0.3220 0.3200 0.3300
    Triad: 518.9189 0.3760 0.3700 0.3800

    DDR RAM
    Your clock granularity/precision appears to be 9999 microseconds.
    Each test below will take on the order of 219999 microseconds.
       (= 22 clock ticks)
    -------------------------------------------------------------
    Function Rate (MB/s) RMS time Min time Max time
    Copy: 533.3333 0.2451 0.2400 0.2500
    Scale: 581.8182 0.2291 0.2200 0.2400
    Add: 738.4615 0.2711 0.2600 0.2800
    Triad: 711.1111 0.2771 0.2700 0.2900

    Ratios:
    Copy: 533.3333 / 474.0741 = ~1.125
    Scale: 581.8182 / 474.0741 = ~1.227
    Add: 738.4615 / 600.0000 = ~1.231
    Triad: 711.1111 / 518.9189 = ~1.370

    Just in case the version of the gcc was effecting the results
    I tried the binary made with the old version in the new PC:

    -------------------------------------------------------------
    Function Rate (MB/s) RMS time Min time Max time
    Copy: 556.5217 0.2370 0.2300 0.2400
    Scale: 581.8182 0.2280 0.2200 0.2300
    Add: 738.4615 0.2680 0.2600 0.2700
    Triad: 685.7143 0.2921 0.2800 0.3000 

    -- 
rps

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