IDE Controler CMD 0649 PIO Mode 4 only

Discussion in 'Windows Vista Hardware' started by Flash, Sep 17, 2006.

  1. Flash

    Flash Guest

    I use the IDE Controller CMD 0649 chipset for my DVDRRW optical rives the
    controller is capable of ATA 100. Device Manager shows it as PIO mode 4 &
    the Enable DMA box is disabled.
    Editing the registry manually I am able to change to DMA mode but it resets
    upon a reboot.
    Flash, Sep 17, 2006
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  2. First thing to check is that you have an 80 wire cable and not an old 40
    Cari \(MS-MVP\), Sep 17, 2006
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  3. Flash

    Peter M Guest

    PIO 4 is actually multi-word dma 2 which is what many optical drives still
    only run at.
    Peter M, Sep 18, 2006
  4. Flash

    Flash Guest

    Firstly I must point out that I have Dual Boot and am running XP Pro on the
    same PC for 2 years without any DMA issues
    I have six DVDRW drives in the system using 3 IDE controllers all with 80
    wire ATA-133cables
    4 drives should operate at Ultra DMA Mode 2 & two should operate at Ultra
    DMA Mode 4. They operate successfully at these settings when I boot up into
    XP Pro.
    In PIO mode 4 excessive CPU usage is noticed and the writing speed is
    restricted to 4x, this is as expected with PIO mode
    Using a Pioneer burner on the M/B IDE channel I can get the correct Ultra
    DMA Mode 4, but unfortunately I do not have any spare IDE on my M/B

    The issue is with the controller drivers supplied with the OS and not the
    hardware set up
    Flash, Sep 18, 2006
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