amd - CPU lost a core?

07
2014-07

sealz

I have a quad core processor. AMD Phenom II x4 965 3.4 MHz Which is about a year old. It has never been overheated and has never really been stressed for any long periods of time. I don't think I've seen the usage get over 50% even when doing heavy computing. Its a sweet lil processor :)

When my Motherboard boots up it always says how many cores it loaded. Recently it is now only loading 3.

It states roughly "3x cores loaded (0,1,2)"

I am also monitoring my CPU temps with windows 7 gadgets and that too now only picks up 3 cores?

What would have caused a core to vanish all of a sudden? Do I need to update BIOS and what do I risk in doing that?

Answers

Mantis

It sounds like the processor might be defective. You should contact AMD or your computer manufacturer to request a replacement. Many processors have manufacturer's warranties covering the product for one year or longer.

In case you would like to do further diagnostics, try downloading CPU-Z or a similar tool that can get some basic information about the processor and display it to you.

You could also try updating or re-flashing the BIOS. It's unlikely, but possible, that the BIOS has a bug that is preventing your processor from working correctly. Keep in mind that there is always a risk in updating the BIOS. If you lose power during a BIOS update, it might render your system unusable. Be sure to keep a charged battery in place if this is a laptop, and don't update BIOS during a time when the power supply is unreliable (like during a storm).

Moab

Check Msconfig, Boot Tab > Advanced Options

Number of Processors should be Unchecked, along with everything else, if it is not, uncheck it, hit OK and reboot. Unchecked means use all cores and threads.

Some more info in my post here

enter image description here

Waxhead

Unless the AMD processor have some exceptionally smart redundancy built in I doubt there is something wrong with your processor. It is more likely that either Windows is not picking up the correct count or that your BIOS is failing.

Also remember that even if you are shutting down your computer there usually is power on the mainboard. None of that should be reaching the CPU but you can try to unplug your computer from the wall, hit the powerbutton (to dischagre any capacitors), plug your computer in the wall socket again and start up to see if something changes.

I also suggest starting up from a linux live cd, go to a terminal and write cat /proc/cpuinfo.

Related Question

What do "processor" and "cpu cores" mean in /proc/cpuinfo?

cpu cpu-cores

why

Possible Duplicate:
Difference Between Cores and Processors

What do "processor" and "cpu cores" mean here?

cat /proc/cpuinfo 
    processor   : 0
    vendor_id   : GenuineIntel
    cpu family  : 6
    model       : 15
    model name  : Intel(R) Core(TM)2 Duo CPU     T5670  @ 1.80GHz
    stepping    : 13
    cpu MHz     : 1801.000
    cache size  : 2048 KB
    physical id : 0
    siblings    : 2
    core id     : 0
    cpu cores   : 2
    apicid      : 0
    initial apicid  : 0
    fdiv_bug    : no
    hlt_bug     : no
    f00f_bug    : no
    coma_bug    : no
    fpu     : yes
    fpu_exception   : yes
    cpuid level : 10
    wp      : yes
    flags       : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm lahf_lm ida dts
    bogomips    : 3591.62
    clflush size    : 64
    cache_alignment : 64
    address sizes   : 36 bits physical, 48 bits virtual
    power management:

    processor   : 1
    vendor_id   : GenuineIntel
    cpu family  : 6
    model       : 15
    model name  : Intel(R) Core(TM)2 Duo CPU     T5670  @ 1.80GHz
    stepping    : 13
    cpu MHz     : 800.000
    cache size  : 2048 KB
    physical id : 0
    siblings    : 2
    core id     : 1
    cpu cores   : 2
    apicid      : 1
    initial apicid  : 1
    fdiv_bug    : no
    hlt_bug     : no
    f00f_bug    : no
    coma_bug    : no
    fpu     : yes
    fpu_exception   : yes
    cpuid level : 10
    wp      : yes
    flags       : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm lahf_lm ida dts
    bogomips    : 3590.97
    clflush size    : 64
    cache_alignment : 64
    address sizes   : 36 bits physical, 48 bits virtual
    power management:

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amd - CPU lost a core?