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Windows 7 showing only 4 threads instead of 8 for Core i7 860?!

Hi,

I'm having an wierd problem with my computer.

Motherboard = Gigabyte GA-P55-UD3
Procesor = INTEL CORE i7 860 2.80 GHz

Motherboar BIOS (updated to latest version F5) is set to default settings.

OS = Windows 7 Professional 64 bit.

Check out the print-screens:

1.


Device manager properly shows 8 logical processors (4 cores x 2 with Multi-Threading)!


2.


But Task Manager shows ONLY 4 logical processors.


3.


Also CPU-Z and CoreTemp shows only 2 cores and 4 threads.

---

I tried to disable Multi-Threading in BIOS and then CPU-Z and CoreTemp shows 4 cores.

It looks like my OS is limiting CPU to 4 logical threads? Is this possible? Are there any CPU affinity modes settings in Windows 7?



Thanks for help!

Kind regards, Marko Kobal.
19 answers Last reply
More about windows showing threads core
  1. This must be by far the wierdest thing I have seen on an intel core i7 O.o

    But from my point of view it could be the OS(As you said) or the motherboard that for some reason isnt recognizing the threads and the cores. It could be aswell a foulty CPU but thats rare, or it could be a foulty installation of the CPU. Check if you got the "arrows" positioned right.

    Here is what I would do:

    1#Check the BIOS and see if it provides the same information
    2#If the BIOS has correct info about the CPU, reinstall windows or test another version of windows
    3#Open up the rig and reinstall the CPU
    4#Open the rig take the CPU out and throw it out of the window


    Im not sure I helped or made the situation worse but hey, you have to try ;D


    Erik Jansson
    ////UPDATE////
    Just noticed a thing on those pics, on the core temp picture its saying Intel core i3 O.o, something on that CPU of yours is reaaaaallllllyyy wierd. And btw those are pretty nice temps u got there what cooler are u using?
  2. EDIT: never mind. I would folow what erikjansson said.
  3. markokobal said:
    It looks like my OS is limiting CPU to 4 logical threads? Is this possible? Are there any CPU affinity modes settings in Windows 7?


    No, it should be able to display 8 threads.

  4. markokobal said:
    Hi,

    I'm having an wierd problem with my computer.

    Motherboard = Gigabyte GA-P55-UD3
    Procesor = INTEL CORE i7 860 2.80 GHz

    Motherboar BIOS (updated to latest version F5) is set to default settings.

    OS = Windows 7 Professional 64 bit.

    Check out the print-screens:

    1.
    http://personal.arctur.si/marko/stuff/core_i7/Device_Manager_8_CPU_4cores_x2_multi-threading.png

    Device manager properly shows 8 logical processors (4 cores x 2 with Multi-Threading)!


    2.
    http://personal.arctur.si/marko/stuff/core_i7/Task_Manager_4_CPU_2cores_x2_multi-threading.png

    But Task Manager shows ONLY 4 logical processors.


    3.
    http://personal.arctur.si/marko/stuff/core_i7/CPU-Z_and_CoreTemp_2cores_x2_multi-threading.png

    Also CPU-Z and CoreTemp shows only 2 cores and 4 threads.

    ---

    I tried to disable Multi-Threading in BIOS and then CPU-Z and CoreTemp shows 4 cores.

    It looks like my OS is limiting CPU to 4 logical threads? Is this possible? Are there any CPU affinity modes settings in Windows 7?



    Thanks for help!

    Kind regards, Marko Kobal.


    That's pretty odd behavior. It is possible you've caught a defective part, but I've never heard of this failure mode before.

    I'd call "BIOS" on this one, especially since you've verified that changing the BIOS changes the reported CPU-Z results. Since you said this is the latest BIOS, can you switch to an older one and see if this behavior changes?
  5. is hyperthreading enabled in the bios ??
  6. Hi,

    Thanks for the answers. I'll add some more details on this story:

    1. Multi-Threading is enabled in BIOS.

    2. Like I said - when I disable Multi-Threading, there are 4 cores shown (insted of only 2 when Multi-Threading is enabled).

    I remember, when I first installed Win7, there were all 8 threads (logical CPU's) shown in Task Manger.

    Later I've disabled Multi-Threading and reinstalled Win7 (because of some applications wich performs better without Multi-Threading). Now I have again enabled Multi-Threading, but it seams like Win7 somehow "set" the maximum number of logical processor to 4 at installation, beacuse that was the number at the time of installation of Win7.

    Wierd ... anyway ... I'll try to reinstall Win7 on another disk with Multi-Threading enabled before installation and check if it will then use all 8 logical processors.

    Kind regards, Marko Kobal.
  7. Question: I thought the P55 i7's weren't capable of multithreading (and thus, only capable for 4 threads)?
  8. Nope. P55 i7s are 4 core, 8 thread. P55 i5s are 4 core, 4 threads.
  9. archibael said:
    Nope. P55 i7s are 4 core, 8 thread. P55 i5s are 4 core, 4 threads.


    +1

    Core i7 p55 act just the same as core i7 x58 cpus. (in the term of thread count.)
  10. Actually, I should have said "1156" instead of "P55". Clarkdale i5s are 4 thread, 2 core.
  11. archibael said:
    Actually, I should have said "1156" instead of "P55". Clarkdale i5s are 4 thread, 2 core.


    The way i see it,

    Core i5 will always have a total of 4 threads while core i7 (excluding the core i7 980/core i9) has 8 threads.
  12. That's how I remember it, yes.
  13. Hi. Hope this might help unless u already have sorted it. But there might be other out there wanna know the solution. Now this is in general to rule out issues with one or more of the multiple cores and is by default unboxed. You can read more here: BOOT advanced option
    Anyway, here it is a quick check for you(this is also in the abow link):

    type "administrative tools" in the search bar on Start and klick it.
    This will open a window for you. You will there choose "system configuration"
    Klick on the tab "Boot" and choose "advanced options". U might have selected number of processors. Uncheck the box and accept.
    Reboot is necessary.

    Hope that sorts your problem ;-)

    Best regards / Profet
  14. i think its the BIOS ... i just updated from F2 to F5 and instantly lost 2 cores .. ( even in CMOS, when entering the menu to check CPU temps id lost two cores ) ... i then stepped down to f4 and f3, same problem

    reflashed f2 and the cores reappeared.. bit of a bummer given that from that ive read f4 is apparently better suited to win 7 and o/c

    might see if i can contact gb for answer

    core i7 860
    gb p55-ud4
    8gb ddr3 1333
    750w p/s
    2 x radeon hd 5850
  15. further invetigation found a really simple answer... when upgraded bios it defaulted to only activating 2 cores... just have to switch number of calls back to all and in action ...
  16. Hi,
    I Have exactly the same problem as markokobol but with a Core i7 and Gigabyte GA EX58 UD3R. I've tried most of the suggestions below but to no avail.
    Anyone any more ideas, please!?
  17. Ooops, sorry, that should have been Core i7 920...
  18. Thanks for this - it helped me as I had forgotten I had fiddled with the Boot options!
  19. This topic has been closed by Mousemonkey
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