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  • disabling one of the cpu

    Hi,

    Is there any way to disable one of the cpu at OS or BIOS level with out physically removing. I am running windows 2000 server with SP4 in Dell poweredge 2400 Series. It has two Intel xeon CPU.

    Any Ideas.


    Thanx in advance.
    SKM

  • #2
    Re: disabling one of the cpu

    Device Manager
    Computer
    Multiprocessor PC
    Update Driver
    Install from a list or specific location (Advanced)
    Don't search. I will choose a driver to install and select the Uniprocessor (MPS or ACPI)

    Try that and see how you go.
    1 1 was a racehorse.
    2 2 was 1 2.
    1 1 1 1 race 1 day,
    2 2 1 1 2

    Comment


    • #3
      Re: disabling one of the cpu

      Originally posted by biggles77
      Device Manager
      Computer
      Multiprocessor PC
      Update Driver
      Install from a list or specific location (Advanced)
      Don't search. I will choose a driver to install and select the Uniprocessor (MPS or ACPI)

      Try that and see how you go.
      Before doing that try setting NUMPROC=1 in the boot.ini.

      If you don't actually have 2 physical CPUs then you're using Hyperthreading which needs to be disabled in the BIOS.
      Last edited by ahinson; 23rd December 2005, 03:57.
      Andrew

      ** Remember to give credit where credit is due and leave reputation points sigpic where appropriate **

      Comment


      • #4
        Re: disabling one of the cpu

        Originally posted by skm_mail
        Hi,

        Is there any way to disable one of the cpu at OS or BIOS level with out physically removing. I am running windows 2000 server with SP4 in Dell poweredge 2400 Series. It has two Intel xeon CPU.

        Any Ideas.


        Thanx in advance.
        SKM
        Is your CPU DUAL CORE or having two physical CPU ?!

        Comment


        • #5
          Re: disabling one of the cpu

          two Physical CPU.

          SKM

          Comment


          • #6
            Re: disabling one of the cpu

            Did you try either Andrew's or my way? I am curious to know if NUMPROC=1 works in this case.
            1 1 was a racehorse.
            2 2 was 1 2.
            1 1 1 1 race 1 day,
            2 2 1 1 2

            Comment


            • #7
              Re: disabling one of the cpu

              Hi,

              It tried NUMPROC=1, its not working. From where did you got this info. was it working for you. I think the driver conversion might work, but if i convert again to acpi mulitiprocessor then OS the will crash, because i tried this already on another server which failed to detect dual CPU. So again i had to resintall the OS.

              SKM

              Comment


              • #8
                Re: disabling one of the cpu

                Originally posted by skm_mail
                I tried NUMPROC=1, its not working. From where did you got this info. was it working for you...
                Make sure you're using it correctly. My information came directly from Microsoft. Why, are you questioning me? j/k
                I used it once before but only to benchmark 1 vs 2 cpus running Quake 2 on NT 4 (If I recall it made no difference). I haven't used it since but the option is still there.

                http://support.microsoft.com/default...21120121120120
                Last edited by ahinson; 27th December 2005, 07:12.
                Andrew

                ** Remember to give credit where credit is due and leave reputation points sigpic where appropriate **

                Comment


                • #9
                  Re: disabling one of the cpu

                  I have always thought that Windows uses a different HAL when using 2 processors.

                  I could be wrong though

                  Comment


                  • #10
                    Re: disabling one of the cpu

                    Hi,

                    Thanx for the link. But this switch option is applicable only for windows 2003/xp OS according to this MS Kbase.

                    Also I tried to downgrade the driver from acpi multiprocessor to acpi uniprocessor. It worked. Again i converted to multiprocessor. It worked very well. But this is a very risky process. There is high possibility for OS getting crashed. Because Some 6 months back i tried this process for one my server which is a critical prodcution server. The OS got crashed, & I have to resintall & resotored the data from backup. So I was scary.

                    Also i will try this /numproc=number switch option in windows 2003 server. And I will post the result here.


                    Thanx for sharing all ur technical Knowledge.


                    SKM

                    Comment


                    • #11
                      Re: disabling one of the cpu

                      Originally posted by skm_mail
                      Thanx for the link. But this switch option is applicable only for windows 2003/xp OS according to this MS Kbase.
                      Um, okay...

                      I'm glad changing the Computer type worked for you but like you said it can nuke your system.

                      That switch has been around since Windows NT 4 and will work in NT/2000/2003/XP. If it didn't work try using /ONECPU instead.

                      /NUMPROC=
                      Specifies the number of CPUs that can be used on a multiprocessor system. Example: /NUMPROC=2 on a four-way system will prevent Windows from using two of the four processors.
                      /ONECPU
                      Causes Windows to use only one CPU on a multiprocessor system.
                      Andrew

                      ** Remember to give credit where credit is due and leave reputation points sigpic where appropriate **

                      Comment


                      • #12
                        Re: disabling one of the cpu

                        Just Now I tried for Windows 2000 OS


                        /numproc=number switch option works. Great! It works well for Windows 2000 Server/Professional & 2003/XP.


                        Than U very much for sharing ur knowledge.


                        SKM

                        Comment


                        • #13
                          Re: disabling one of the cpu

                          Also, just as an added bit of information. You shouldn't have to rebuild your OS just because you change your HAL. Here is the MS Article.

                          http://support.microsoft.com/kb/237556/

                          I used to use this procedure a lot when restoring production machines into my test lab from tape. My test lab machines did not always have the same CPU count as my production machines. This is also useful for VMWARE.

                          I have successfully used this procedure many times.

                          Its as simple as extracting the correct HAL and copying it to the machine.
                          I just had them both sitting on floppies and copied the appropriate one when needed. (From recovery console after booting to CD)

                          ACPI Multiprocessor PC = Halmacpi.dll
                          ACPI Uniprocessor PC = Halaacpi.dll

                          Oh, here is another article.

                          http://support.microsoft.com/kb/249694/en-us

                          Hope this helps.

                          Ken Aldrich
                          Senior Support Engineer
                          Visual Click Software
                          [email protected]
                          Ken
                          Senior Support Engineer
                          Visual Click Software
                          512-231-9990 x 2
                          UK Support: 0800 814 1317

                          Comment


                          • #14
                            Re: disabling one of the cpu

                            Originally posted by kDSRAZOR
                            Also, just as an added bit of information. You shouldn't have to rebuild your OS just because you change your HAL. Here is the MS Article.

                            http://support.microsoft.com/kb/237556/

                            I used to use this procedure a lot when restoring production machines into my test lab from tape. My test lab machines did not always have the same CPU count as my production machines. This is also useful for VMWARE.

                            I have successfully used this procedure many times.

                            Its as simple as extracting the correct HAL and copying it to the machine.
                            I just had them both sitting on floppies and copied the appropriate one when needed. (From recovery console after booting to CD)

                            ACPI Multiprocessor PC = Halmacpi.dll
                            ACPI Uniprocessor PC = Halaacpi.dll

                            Oh, here is another article.

                            http://support.microsoft.com/kb/249694/en-us

                            Hope this helps.

                            Ken Aldrich
                            Senior Support Engineer
                            Visual Click Software
                            [email protected]
                            kDSRAZOR,

                            Thank you for sharing. Hopefully someone can benefit from your knowledge. Hope to you see around Petri.co.il more frequently.

                            Andrew
                            Andrew

                            ** Remember to give credit where credit is due and leave reputation points sigpic where appropriate **

                            Comment

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