Promise PDC20276 in ATA133 mode: High CPU usage?

Discussion in 'Gigabyte' started by Will Dormann, May 6, 2004.

  1. Will Dormann

    Will Dormann Guest


    I've got a GA-7DXR+ that has an onboard Promise PDC20276 (MBUltra133)
    controller. It can be set for either RAID mode or ATA133 mode in the

    When in ATA133 mode, I've noticed that the CPU usage is very high when
    copying a large test file from a drive on it to a drive on my normal
    onboard IDE controller. According to the Win2k task manager, it's about
    80% CPU usage, with nearly all of that Kernel time.

    In a older thread, somebody recommended using the controller in RAID
    mode with just the single drive, using the Promise RAID driver. This
    actually did fix the CPU usage problem for me, but I'm concerned that I
    cannot access the drive's SMART data in this configuration. And my
    Acronis TrueImage recovery CD seems to be somewhat unstable when reading
    an image off of the drive on the 20276. (At least in RAID mode...
    haven't gotten around to testing ATA133 stability)

    I'm currently using the 2.00.1020.41 version of the MBUltra133 driver.
    A user in another old thread mentioned that he was using the "20"
    version of the driver without any abnormal CPU usage, but I could not
    find that version anywhere.

    Is anybody here using their PDC20276 in ATA133 mode without any
    excessive CPU usage? If so, what's your secret?

    Would I be better off getting a PCI IDE controller and using it instead?
    Any models to avoid? (Promise??)

    Will Dormann, May 6, 2004
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  2. Will Dormann

    Will Dormann Guest

    Just a follow up to my original post...

    I tried setting up the PC so that the two hard drives were both on the
    onboard IDE controller (different channels), and the CPU usage was
    pretty similar. I thought that the CPU usage should be lower because
    of DMA and such, but I guess I was wrong.

    ATA133 mode has the same problems. I think it's an issue with linux
    and the PDC20276 chip.

    Will Dormann, May 6, 2004
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  3. Will Dormann

    NuTCrAcKeR Guest

    i think its more likely an issue with IDE RAID.. they all have high CPU
    util, no matter what OS.

    Now SCSI Raid has virtually no CPU overhead which is why real servers use
    SCSI and not IDE raid.

    NuTCrAcKeR, May 18, 2004
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