Why is the number of logical cores in my Intel Pentium Dual Core suddenly reduced?

Asif Mistry May 2, 2012
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I have a Intel Pentium D 3.0GHz which is Dual Core, but recently the task manager showed single processor. I have checked it with CPU Z, even it started showing single core, but the clock speed is same (3GHz). It used to show Dual Core before. The performance also degraded.

  1. ha14
    May 2, 2012 at 9:57 pm

    motherboard problem? bios Settings problem?(see if you disabled multi core) or that your Processor is end of life?

    reset bios, reset cmos battery

    Fresh Install of XP to consider

    A geeks guide to Windows XP HAL Replacement
    http://www.myitforum.com/articles/15/view.asp?id=8997

    HAL options after Windows XP or Windows Server 2003 Setup.
    http://support.microsoft.com/kb/309283

  2. Bruce Epper
    May 2, 2012 at 8:07 pm

    Were there any changes to the operating system on this sytem? Replacing the SMP HAL with the uniprocessor HAL will do that. This would be the most likely cause since I have yet to see a machine with the SMP HAL function at all with only a single processing core.

    • ASIF
      May 4, 2012 at 6:00 pm

      I dont really understand what is smp hal and I have been using Windows 7 since a year or 2

      • Bruce Epper
        May 5, 2012 at 8:10 pm

        My bad. Made the same assumption that ha14 did that you were using XP. IIRC, Vista and 7 don't install different uniprocessor or multiprocessor HALs. The HAL was adapted to work with single or multiple processors. In that case, reboot the machine and enter your BIOS setup program. There should be an option in there that indicates how many cores the BIOS is detecting (generally not user-selectable, just there for you to see it detects it properly). If it is only showing a single core, one of the cores in the chip may be damaged or the motherboard itself could have an issue. The only reliable way to determine that is to swap the processor out into another supported motherboard to see if it reports the same thing. If it does, the problem is the processor chip, otherwise it is the motherboard.