Professional Help: Getting The Best Overclock From AMD's A8-3870K

Benchmark Results: DiRT 3

DiRT 3 stands in as a good representative of simulator titles. The A8-3870K can handle it at 1920x1080 with 2x MSAA at the Low detail preset.

DiRT 3 is another title that derives much of its performance from available memory bandwidth. Unfortunately, the overclocked A8-3870K’s best effort falls notably short of the Radeon HD 6670 DDR3.

The only significant difference between this test and the last one is added anti-aliasing (a notoriously bandwidth-dependent effect). It's probable that the APU's shared memory architecture is simply not as well-suited for throughput-intensive details as a discrete card.

The gap between discrete graphics and the APU is even clearer when we look at frame rates over time.

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  • HEXiT
    cool... nice to get the input from some 1 who actually knows his apples.... rather than putting up a white board and saying this is what will happen in theory...
  • demtibor

    The article is good..but...

    If i can recommend something : Throw out the Vengeance modules, use more potent ones which can do around 2400 or above. As i noticed, Llano's memory controller has around 10% handicap compared to discrete solutions which means it's DDR3-2200 is roughly equal with discrete DDR3-2000. Of course this highly depends on the used timings.

    Here are my 24/7 Llano settings :

    ASUS F1A75-V Evo, 3870K, 2x2GB Geil EVO 2200 CL9, Freezer Pro 13.

    -125 BCLK
    -28x CPU multiplier (3500 Mhz ) with 1.475V
    -9,33x memory ( resulting 2333 Mhz memory clock ) with 9-11-9-28-2T-33-4-4-4 Timings. ( NB is around 1125 mhz as it has 9x ).
    -800 Mhz GPU clock ( resulting 1Ghz GPU in real because of the higher BCLK ).

    At this point i feel that memory performance is still a bottleneck. To be honest the board is capable of operating at 150 BLCK ( especially with the newest 1803 bios which solved the long-boot-time problem ( so far above 110 it took several seconds to initialize and post ) ) but there is no option to lower the north-bridge multiplier, and Llano does not tolerate well NB clock above 1125, even tough with voltage raising. It can operate in windows with 1200 NB, but will fail in 3D immediately. No matter how high voltage you apply.

    I have asked Asus to include that damn divider in their BIOS, unfortunately they rejected my request.