Hyperthreading

Discussion in 'Windows 64bit' started by Chuck Goldstein, Jul 18, 2005.

  1. Hyperthreading is turned OFF in the bios. When should it be ON? My x64 PC
    has 2 processors.

    Chuck
     
    Chuck Goldstein, Jul 18, 2005
    #1
    1. Advertising

  2. Yes, Hyperthreading is supported under x64, it should show up under Task
    Manager as two processors.

    Check out the following link which tells you about Hyperthreading, its
    purpose and how to set it up:
    http://www.intel.com/support/processors/pentium4/sb/CS-017371.htm
    --
    Andre
    Extended64 | http://www.extended64.com
    Blog | http://www.extended64.com/blogs/andre
    http://spaces.msn.com/members/adacosta
    FAQ for MS AntiSpy http://www.geocities.com/marfer_mvp/FAQ_MSantispy.htm

    "Chuck Goldstein" <> wrote in message
    news:...
    > Hyperthreading is turned OFF in the bios. When should it be ON? My x64
    > PC has 2 processors.
    >
    > Chuck
    >
     
    Andre Da Costa [Extended64], Jul 18, 2005
    #2
    1. Advertising

  3. "Chuck Goldstein" <> wrote in message
    news:...
    > Hyperthreading is turned OFF in the bios. When should it be ON? My x64
    > PC has 2 processors.
    >


    It should be ON in the BIOS when you want to enable the hyper threading on
    your two processors,
    Doing so will then display 4 CPUs in Task Manager.

    --

    Regards,

    Mike
    --
    Mike Brannigan [Microsoft]

    This posting is provided "AS IS" with no warranties, and confers no
    rights

    Please note I cannot respond to e-mailed questions, please use these
    newsgroups

    "Chuck Goldstein" <> wrote in message
    news:...
    > Hyperthreading is turned OFF in the bios. When should it be ON? My x64
    > PC has 2 processors.
    >
    > Chuck
    >
     
    Mike Brannigan [MSFT], Jul 18, 2005
    #3
  4. If you turn it on in BIOS, you'll see an apparent 4 processors. But before
    you do that, think about the workload your machine does. Would it really
    benefit from 4 processors over 2? Certainly few if any workstations need or
    would use 4 processors. Two? yes, definitely, and I turn on HT on my single
    proc workstations. But there is overhead in the # of processors, and
    hyperthreading is NOT the same as actually having a dual core processor. So I
    would almost certainly not turn on HT for an actual dual processor machine.
    On a server, now, that's a different question and depends on the workload.

    --
    Please, all replies to the newsgroup.
    ======================
    Charlie.
    http://www.msmvps.com/xperts64/


    Chuck Goldstein wrote:
    > Hyperthreading is turned OFF in the bios. When should it be ON? My
    > x64 PC has 2 processors.
    >
    > Chuck
     
    Charlie Russel - MVP, Jul 19, 2005
    #4
  5. "Charlie Russel - MVP" <> wrote in message
    news:...
    > If you turn it on in BIOS, you'll see an apparent 4 processors. But before
    > you do that, think about the workload your machine does. Would it really
    > benefit from 4 processors over 2? Certainly few if any workstations need
    > or would use 4 processors. Two? yes, definitely, and I turn on HT on my
    > single proc workstations. But there is overhead in the # of processors,
    > and hyperthreading is NOT the same as actually having a dual core
    > processor. So I would almost certainly not turn on HT for an actual dual
    > processor machine. On a server, now, that's a different question and
    > depends on the workload.



    Charlie,

    The "overhead" in managing multiple CPUs is far outweighed by the additional
    processing capability provided (obviously only up to a certain number of
    CPUs), so in the case of workstation class machines (single or dual
    socketed) I would certainly turn on HT for both CPUs.
    Obviously this is an extremely high level view and generalisation as yes
    workload can impact the potential performance gains for a HT system, but
    under "normal" applications and work patterns most "average" users might as
    well get the benefit from the CPUs they have purchased and use HT if
    available.

    --

    Regards,

    Mike
    --
    Mike Brannigan [Microsoft]

    This posting is provided "AS IS" with no warranties, and confers no
    rights

    Please note I cannot respond to e-mailed questions, please use these
    newsgroups

    "Charlie Russel - MVP" <> wrote in message
    news:...
    > If you turn it on in BIOS, you'll see an apparent 4 processors. But before
    > you do that, think about the workload your machine does. Would it really
    > benefit from 4 processors over 2? Certainly few if any workstations need
    > or would use 4 processors. Two? yes, definitely, and I turn on HT on my
    > single proc workstations. But there is overhead in the # of processors,
    > and hyperthreading is NOT the same as actually having a dual core
    > processor. So I would almost certainly not turn on HT for an actual dual
    > processor machine. On a server, now, that's a different question and
    > depends on the workload.
    >
    > --
    > Please, all replies to the newsgroup.
    > ======================
    > Charlie.
    > http://www.msmvps.com/xperts64/
    >
    >
    > Chuck Goldstein wrote:
    >> Hyperthreading is turned OFF in the bios. When should it be ON? My
    >> x64 PC has 2 processors.
    >>
    >> Chuck

    >
    >
     
    Mike Brannigan [MSFT], Jul 19, 2005
    #5
  6. Chuck Goldstein

    NNBXX Guest

    I agree with you, Mike. I am using a dual Xeon EM64T workstation. Two
    processors without HT are far better than one for 3D rendering (almost twice
    as fast, actually). But with HT turned on for both processors, 3D rendering
    is still 15-20% faster, which is not negligible, IMO.

    "Mike Brannigan [MSFT]" <> wrote in message
    news:eZIU7$...
    > "Charlie Russel - MVP" <> wrote in message
    > news:...
    >> If you turn it on in BIOS, you'll see an apparent 4 processors. But
    >> before you do that, think about the workload your machine does. Would it
    >> really benefit from 4 processors over 2? Certainly few if any
    >> workstations need or would use 4 processors. Two? yes, definitely, and I
    >> turn on HT on my single proc workstations. But there is overhead in the #
    >> of processors, and hyperthreading is NOT the same as actually having a
    >> dual core processor. So I would almost certainly not turn on HT for an
    >> actual dual processor machine. On a server, now, that's a different
    >> question and depends on the workload.

    >
    >
    > Charlie,
    >
    > The "overhead" in managing multiple CPUs is far outweighed by the
    > additional processing capability provided (obviously only up to a certain
    > number of CPUs), so in the case of workstation class machines (single or
    > dual socketed) I would certainly turn on HT for both CPUs.
    > Obviously this is an extremely high level view and generalisation as yes
    > workload can impact the potential performance gains for a HT system, but
    > under "normal" applications and work patterns most "average" users might
    > as well get the benefit from the CPUs they have purchased and use HT if
    > available.
    >
    > --
    >
    > Regards,
    >
    > Mike
    > --
    > Mike Brannigan [Microsoft]
    >
    > This posting is provided "AS IS" with no warranties, and confers no
    > rights
    >
    > Please note I cannot respond to e-mailed questions, please use these
    > newsgroups
    >
    > "Charlie Russel - MVP" <> wrote in message
    > news:...
    >> If you turn it on in BIOS, you'll see an apparent 4 processors. But
    >> before you do that, think about the workload your machine does. Would it
    >> really benefit from 4 processors over 2? Certainly few if any
    >> workstations need or would use 4 processors. Two? yes, definitely, and I
    >> turn on HT on my single proc workstations. But there is overhead in the #
    >> of processors, and hyperthreading is NOT the same as actually having a
    >> dual core processor. So I would almost certainly not turn on HT for an
    >> actual dual processor machine. On a server, now, that's a different
    >> question and depends on the workload.
    >>
    >> --
    >> Please, all replies to the newsgroup.
    >> ======================
    >> Charlie.
    >> http://www.msmvps.com/xperts64/
    >>
    >>
    >> Chuck Goldstein wrote:
    >>> Hyperthreading is turned OFF in the bios. When should it be ON? My
    >>> x64 PC has 2 processors.
    >>>
    >>> Chuck

    >>
    >>

    >
    >
     
    NNBXX, Jul 19, 2005
    #6
  7. Interesting, Mike. I don't have a dual proc machine that also supports
    hyperthreading, so I certainly can't directly test this. But I am surprised
    that you think that a "normal" user (which on this group would definitely
    mean a power user) would see much benefit beyond two full procs. Guess I'm
    just going to have to afford some better machines. ;)

    --
    Please, all replies to the newsgroup.
    ======================
    Charlie.
    http://www.msmvps.com/xperts64/


    Mike Brannigan [MSFT] wrote:
    > "Charlie Russel - MVP" <> wrote in
    > message news:...
    >> If you turn it on in BIOS, you'll see an apparent 4 processors. But
    >> before you do that, think about the workload your machine does.
    >> Would it really benefit from 4 processors over 2? Certainly few if
    >> any workstations need or would use 4 processors. Two? yes,
    >> definitely, and I turn on HT on my single proc workstations. But
    >> there is overhead in the # of processors, and hyperthreading is NOT
    >> the same as actually having a dual core processor. So I would almost
    >> certainly not turn on HT for an actual dual processor machine. On a
    >> server, now, that's a different question and depends on the workload.

    >
    >
    > Charlie,
    >
    > The "overhead" in managing multiple CPUs is far outweighed by the
    > additional processing capability provided (obviously only up to a
    > certain number of CPUs), so in the case of workstation class
    > machines (single or dual socketed) I would certainly turn on HT for
    > both CPUs. Obviously this is an extremely high level view and
    > generalisation as
    > yes workload can impact the potential performance gains for a HT
    > system, but under "normal" applications and work patterns most
    > "average" users might as well get the benefit from the CPUs they have
    > purchased and use HT if available.
    >
    > --
    >
    > Regards,
    >
    > Mike
    >
    > "Charlie Russel - MVP" <> wrote in
    > message news:...
    >> If you turn it on in BIOS, you'll see an apparent 4 processors. But
    >> before you do that, think about the workload your machine does.
    >> Would it really benefit from 4 processors over 2? Certainly few if
    >> any workstations need or would use 4 processors. Two? yes,
    >> definitely, and I turn on HT on my single proc workstations. But
    >> there is overhead in the # of processors, and hyperthreading is NOT
    >> the same as actually having a dual core processor. So I would almost
    >> certainly not turn on HT for an actual dual processor machine. On a
    >> server, now, that's a different question and depends on the workload.
    >>
    >> --
    >> Please, all replies to the newsgroup.
    >> ======================
    >> Charlie.
    >> http://www.msmvps.com/xperts64/
    >>
    >>
    >> Chuck Goldstein wrote:
    >>> Hyperthreading is turned OFF in the bios. When should it be ON? My x64
    >>> PC has 2 processors.
    >>>
    >>> Chuck
     
    Charlie Russel - MVP, Jul 19, 2005
    #7
  8. no, not at all negligible. That's an interesting result -- what application
    is doing the rendering? Is it 32-bit? or 64-bit?

    For me this sort of real user, real world, result is far more meaningful than
    a zillion benchmarks.


    --
    Please, all replies to the newsgroup.
    ======================
    Charlie.
    http://www.msmvps.com/xperts64/


    NNBXX wrote:
    > I agree with you, Mike. I am using a dual Xeon EM64T workstation. Two
    > processors without HT are far better than one for 3D rendering
    > (almost twice as fast, actually). But with HT turned on for both
    > processors, 3D rendering is still 15-20% faster, which is not
    > negligible, IMO.
    > "Mike Brannigan [MSFT]" <> wrote in
    > message news:eZIU7$...
    >> "Charlie Russel - MVP" <> wrote in
    >> message news:...
    >>> If you turn it on in BIOS, you'll see an apparent 4 processors. But
    >>> before you do that, think about the workload your machine does.
    >>> Would it really benefit from 4 processors over 2? Certainly few if
    >>> any workstations need or would use 4 processors. Two? yes,
    >>> definitely, and I turn on HT on my single proc workstations. But
    >>> there is overhead in the # of processors, and hyperthreading is NOT
    >>> the same as actually having a dual core processor. So I would
    >>> almost certainly not turn on HT for an actual dual processor
    >>> machine. On a server, now, that's a different question and depends
    >>> on the workload.

    >>
    >>
    >> Charlie,
    >>
    >> The "overhead" in managing multiple CPUs is far outweighed by the
    >> additional processing capability provided (obviously only up to a
    >> certain number of CPUs), so in the case of workstation class
    >> machines (single or dual socketed) I would certainly turn on HT for
    >> both CPUs. Obviously this is an extremely high level view and
    >> generalisation as
    >> yes workload can impact the potential performance gains for a HT
    >> system, but under "normal" applications and work patterns most
    >> "average" users might as well get the benefit from the CPUs they
    >> have purchased and use HT if available.
    >>
    >> --
    >>
    >> Regards,
    >>
    >> Mike
    >> --
    >> Mike Brannigan [Microsoft]
    >>
    >> This posting is provided "AS IS" with no warranties, and confers no
    >> rights
    >>
    >> Please note I cannot respond to e-mailed questions, please use these
    >> newsgroups
    >>
    >> "Charlie Russel - MVP" <> wrote in
    >> message news:...
    >>> If you turn it on in BIOS, you'll see an apparent 4 processors. But
    >>> before you do that, think about the workload your machine does.
    >>> Would it really benefit from 4 processors over 2? Certainly few if
    >>> any workstations need or would use 4 processors. Two? yes,
    >>> definitely, and I turn on HT on my single proc workstations. But
    >>> there is overhead in the # of processors, and hyperthreading is NOT
    >>> the same as actually having a dual core processor. So I would
    >>> almost certainly not turn on HT for an actual dual processor
    >>> machine. On a server, now, that's a different question and depends
    >>> on the workload. --
    >>> Please, all replies to the newsgroup.
    >>> ======================
    >>> Charlie.
    >>> http://www.msmvps.com/xperts64/
    >>>
    >>>
    >>> Chuck Goldstein wrote:
    >>>> Hyperthreading is turned OFF in the bios. When should it be ON? My x64
    >>>> PC has 2 processors.
    >>>>
    >>>> Chuck
     
    Charlie Russel - MVP, Jul 19, 2005
    #8
  9. Does that mean you are not investing in Acer Ferrari again?
    --
    Andre
    Extended64 | http://www.extended64.com
    Blog | http://www.extended64.com/blogs/andre
    http://spaces.msn.com/members/adacosta
    FAQ for MS AntiSpy http://www.geocities.com/marfer_mvp/FAQ_MSantispy.htm

    "Charlie Russel - MVP" <> wrote in message
    news:...
    > Interesting, Mike. I don't have a dual proc machine that also supports
    > hyperthreading, so I certainly can't directly test this. But I am
    > surprised that you think that a "normal" user (which on this group would
    > definitely mean a power user) would see much benefit beyond two full
    > procs. Guess I'm just going to have to afford some better machines. ;)
    >
    > --
    > Please, all replies to the newsgroup.
    > ======================
    > Charlie.
    > http://www.msmvps.com/xperts64/
    >
    >
    > Mike Brannigan [MSFT] wrote:
    >> "Charlie Russel - MVP" <> wrote in
    >> message news:...
    >>> If you turn it on in BIOS, you'll see an apparent 4 processors. But
    >>> before you do that, think about the workload your machine does.
    >>> Would it really benefit from 4 processors over 2? Certainly few if
    >>> any workstations need or would use 4 processors. Two? yes,
    >>> definitely, and I turn on HT on my single proc workstations. But
    >>> there is overhead in the # of processors, and hyperthreading is NOT
    >>> the same as actually having a dual core processor. So I would almost
    >>> certainly not turn on HT for an actual dual processor machine. On a
    >>> server, now, that's a different question and depends on the workload.

    >>
    >>
    >> Charlie,
    >>
    >> The "overhead" in managing multiple CPUs is far outweighed by the
    >> additional processing capability provided (obviously only up to a
    >> certain number of CPUs), so in the case of workstation class
    >> machines (single or dual socketed) I would certainly turn on HT for
    >> both CPUs. Obviously this is an extremely high level view and
    >> generalisation as
    >> yes workload can impact the potential performance gains for a HT
    >> system, but under "normal" applications and work patterns most
    >> "average" users might as well get the benefit from the CPUs they have
    >> purchased and use HT if available.
    >>
    >> --
    >>
    >> Regards,
    >>
    >> Mike
    >>
    >> "Charlie Russel - MVP" <> wrote in
    >> message news:...
    >>> If you turn it on in BIOS, you'll see an apparent 4 processors. But
    >>> before you do that, think about the workload your machine does.
    >>> Would it really benefit from 4 processors over 2? Certainly few if
    >>> any workstations need or would use 4 processors. Two? yes,
    >>> definitely, and I turn on HT on my single proc workstations. But
    >>> there is overhead in the # of processors, and hyperthreading is NOT
    >>> the same as actually having a dual core processor. So I would almost
    >>> certainly not turn on HT for an actual dual processor machine. On a
    >>> server, now, that's a different question and depends on the workload.
    >>>
    >>> --
    >>> Please, all replies to the newsgroup.
    >>> ======================
    >>> Charlie.
    >>> http://www.msmvps.com/xperts64/
    >>>
    >>>
    >>> Chuck Goldstein wrote:
    >>>> Hyperthreading is turned OFF in the bios. When should it be ON? My
    >>>> x64 PC has 2 processors.
    >>>>
    >>>> Chuck

    >
    >
     
    Andre Da Costa [Extended64], Jul 20, 2005
    #9
  10. No, the Ferrari is coming. Not sure when, but I'm still hopeful this month.
    But might have to wait till august.

    --
    Please, all replies to the newsgroup.
    ======================
    Charlie.
    http://www.msmvps.com/xperts64/


    Andre Da Costa [Extended64] wrote:
    > Does that mean you are not investing in Acer Ferrari again?
    >
    > "Charlie Russel - MVP" <> wrote in
    > message news:...
    >> Interesting, Mike. I don't have a dual proc machine that also
    >> supports hyperthreading, so I certainly can't directly test this.
    >> But I am surprised that you think that a "normal" user (which on
    >> this group would definitely mean a power user) would see much
    >> benefit beyond two full procs. Guess I'm just going to have to
    >> afford some better machines. ;) --
    >> Please, all replies to the newsgroup.
    >> ======================
    >> Charlie.
    >> http://www.msmvps.com/xperts64/
    >>
    >>
    >> Mike Brannigan [MSFT] wrote:
    >>> "Charlie Russel - MVP" <> wrote in
    >>> message news:...
    >>>> If you turn it on in BIOS, you'll see an apparent 4 processors. But
    >>>> before you do that, think about the workload your machine does.
    >>>> Would it really benefit from 4 processors over 2? Certainly few if
    >>>> any workstations need or would use 4 processors. Two? yes,
    >>>> definitely, and I turn on HT on my single proc workstations. But
    >>>> there is overhead in the # of processors, and hyperthreading is NOT
    >>>> the same as actually having a dual core processor. So I would
    >>>> almost certainly not turn on HT for an actual dual processor
    >>>> machine. On a server, now, that's a different question and depends
    >>>> on the workload.
    >>>
    >>>
    >>> Charlie,
    >>>
    >>> The "overhead" in managing multiple CPUs is far outweighed by the
    >>> additional processing capability provided (obviously only up to a
    >>> certain number of CPUs), so in the case of workstation class
    >>> machines (single or dual socketed) I would certainly turn on HT for
    >>> both CPUs. Obviously this is an extremely high level view and
    >>> generalisation as
    >>> yes workload can impact the potential performance gains for a HT
    >>> system, but under "normal" applications and work patterns most
    >>> "average" users might as well get the benefit from the CPUs they
    >>> have purchased and use HT if available.
    >>>
    >>> --
    >>>
    >>> Regards,
    >>>
    >>> Mike
    >>>
    >>> "Charlie Russel - MVP" <> wrote in
    >>> message news:...
    >>>> If you turn it on in BIOS, you'll see an apparent 4 processors. But
    >>>> before you do that, think about the workload your machine does.
    >>>> Would it really benefit from 4 processors over 2? Certainly few if
    >>>> any workstations need or would use 4 processors. Two? yes,
    >>>> definitely, and I turn on HT on my single proc workstations. But
    >>>> there is overhead in the # of processors, and hyperthreading is NOT
    >>>> the same as actually having a dual core processor. So I would
    >>>> almost certainly not turn on HT for an actual dual processor
    >>>> machine. On a server, now, that's a different question and depends
    >>>> on the workload. --
    >>>> Please, all replies to the newsgroup.
    >>>> ======================
    >>>> Charlie.
    >>>> http://www.msmvps.com/xperts64/
    >>>>
    >>>>
    >>>> Chuck Goldstein wrote:
    >>>>> Hyperthreading is turned OFF in the bios. When should it be ON? My x64
    >>>>> PC has 2 processors.
    >>>>>
    >>>>> Chuck
     
    Charlie Russel - MVP, Jul 21, 2005
    #10
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