Dual processors- Why?

Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

Is there a general performance enhancement with dual processor boards
or is there only an advantage with certain applications?

Paul
25 answers Last reply
More about dual processors
  1. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    A better question to ask would be whether a dual processor system
    will outperform a single processor system of the same cost. That would
    probably mean using a faster processor than those used in the dual
    system, a 10,000 rpm hard drive in the single cpu system vs a 7,200
    rpm one in the dual processor system, and perhaps a better video card
    and more ram in the single processor system. A motherboard for dual
    processors is also more expensive than for a single one. If one wants
    to use Windows, XP professional needs to be used with dual processors,
    while XP home can be used with a single processor.

    PaulCsouls wrote:

    > Is there a general performance enhancement with dual processor boards
    > or is there only an advantage with certain applications?
    >
    > Paul
  2. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    "JK" <JK9821@netscape.net> wrote in message
    news:410BD617.F63C5D73@netscape.net...
    > A better question to ask would be whether a dual processor system
    > will outperform a single processor system of the same cost. That would
    > probably mean using a faster processor than those used in the dual
    > system, a 10,000 rpm hard drive in the single cpu system vs a 7,200
    > rpm one in the dual processor system, and perhaps a better video card
    > and more ram in the single processor system. A motherboard for dual
    > processors is also more expensive than for a single one. If one wants
    > to use Windows, XP professional needs to be used with dual processors,
    > while XP home can be used with a single processor.
    >
    > PaulCsouls wrote:
    >
    > > Is there a general performance enhancement with dual processor boards
    > > or is there only an advantage with certain applications?
    > >
    > > Paul
    >
    The dual vs. single question has been tested pretty thoroughly over at Tom's
    Hardware and they seem to think that the dual Xeon has some advantages over
    the fastest P4. I suspect that, like most benchmarking tests, a lot depends
    on which tests you care to run.

    http://www.tomshardware.com/motherboard/20040514/index.html

    --
    John McGaw
    [Knoxville, TN, USA]
    http://johnmcgaw.com
  3. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    "PaulCsouls" <paulcsouls@worldnet.att.net> wrote...
    >
    > Is there a general performance enhancement with dual processor boards
    > or is there only an advantage with certain applications?

    There is a general enhancement.

    Win 2000 and XP Pro can allocate OS tasks among the processors as well as
    individual processes within applications. Also, CPU-intensive background
    apps will work without interfering with foreground tasks running on the
    other CPU. There will be even further enhancement with SMP-aware apps such
    as Photoshop (v5.5 and later).

    As a datapoint, my dual P-III/550 ran the Business Winstone twice as fast as
    my single P-III/1200 laptop.
  4. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    Okay, I'll add some specifics.

    Two Intel Xeon 2.4GHz 533MHz FSB 512 Cache for $222.00 each and a $250
    Motherboard

    VS

    One Athlon 64 3700+ 2.4GHz 1MB Cache for $519.00 and a $75.00 Mother
    board

    Does 64 bits beat 2 processors?

    On Sat, 31 Jul 2004 13:25:43 -0400, JK <JK9821@netscape.net> wrote:

    >A better question to ask would be whether a dual processor system
    >will outperform a single processor system of the same cost. That would
    >probably mean using a faster processor than those used in the dual
    >system, a 10,000 rpm hard drive in the single cpu system vs a 7,200
    >rpm one in the dual processor system, and perhaps a better video card
    >and more ram in the single processor system. A motherboard for dual
    >processors is also more expensive than for a single one. If one wants
    >to use Windows, XP professional needs to be used with dual processors,
    >while XP home can be used with a single processor.
    >
    >PaulCsouls wrote:
    >
    >> Is there a general performance enhancement with dual processor boards
    >> or is there only an advantage with certain applications?
    >>
    >> Paul
  5. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    "JK" <JK9821@netscape.net> wrote...
    > A better question to ask would be whether a dual processor system
    > will outperform a single processor system of the same cost.

    Not necessarily...

    Though you are not likely to be able to find a dual system at the same cost
    as a low-end single-CPU system (except in a used machine, which I just
    happen to have available...), it is likely that a person looking for
    performance is willing to pay for that performance.

    Whether a high-end single-CPU machine will outperform a low-end dual-CPU
    machine depends on both the respective hardware as well as the use to which
    the machine is put. In general, the high-end single will likely outperform
    the dual in a single-app environment, while the dual will work better in a
    multitasking environment. Of course, you can always "choke" any machine by
    underspecifying a single component, such as RAM or HD...
  6. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    "PaulCsouls" <paulcsouls@worldnet.att.net> wrote...
    > Okay, I'll add some specifics.
    >
    > Two Intel Xeon 2.4GHz 533MHz FSB 512 Cache for $222.00 each and a $250
    > Motherboard
    >
    > VS
    >
    > One Athlon 64 3700+ 2.4GHz 1MB Cache for $519.00 and a $75.00 Mother
    > board
    >
    > Does 64 bits beat 2 processors?

    Not yet...

    However, you can have both with a dual Opteron system...
  7. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    On Sat, 31 Jul 2004 15:50:50 -0400, "John McGaw" <nowhere@at.all>
    wrote:
    >>
    >The dual vs. single question has been tested pretty thoroughly over at Tom's
    >Hardware and they seem to think that the dual Xeon has some advantages over
    >the fastest P4. I suspect that, like most benchmarking tests, a lot depends
    >on which tests you care to run.
    >
    >http://www.tomshardware.com/motherboard/20040514/index.html


    Cool link. That pretty much answers my question. Dual processors seem
    to offer little for game playing like Quake and alot for video
    applications. I wonder if DOOM 3 uses hyperthreading.

    Paul
  8. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    That is not a fair comparison, as the hard drive on a notebook is typically
    much slower than the hard drive on a desktop. The graphics subsystem on
    a desktop is also typically much faster than that of a notebook.

    John R Weiss wrote:

    > "PaulCsouls" <paulcsouls@worldnet.att.net> wrote...
    > >
    > > Is there a general performance enhancement with dual processor boards
    > > or is there only an advantage with certain applications?
    >
    > There is a general enhancement.
    >
    > Win 2000 and XP Pro can allocate OS tasks among the processors as well as
    > individual processes within applications. Also, CPU-intensive background
    > apps will work without interfering with foreground tasks running on the
    > other CPU. There will be even further enhancement with SMP-aware apps such
    > as Photoshop (v5.5 and later).
    >
    > As a datapoint, my dual P-III/550 ran the Business Winstone twice as fast as
    > my single P-III/1200 laptop.
  9. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    I expect the Athlon 64 3700+ to be much faster in most applications.
    The Xeon is essentially a Pentium 4 that can be used in a dual
    configuration. You might want to consider an Athlon 64 3800+
    if you plan to do gaming or other high bandwith software, as it
    has dual on chip memory controllers. Also keep in mind that
    with a single Athlon 64 you can use Windows XP home, while a dual
    Xeon system Would require Windows XP professional, so the
    Athlon 64 3800+ would be more compare in price than the Athlon 64 3700+.
    Even with 32 bit software, I would expect the Athlon 64 to come out
    ahead with the vast majority of software. With 64 bit software, the
    Athlon 64 performance would really be superb. Even with a 64 bit OS
    and 32 bit software the Athlon 64 might perform much better in
    many applications than its already great performance running 32
    bit software with a 32 bit OS.

    PaulCsouls wrote:

    > Okay, I'll add some specifics.
    >
    > Two Intel Xeon 2.4GHz 533MHz FSB 512 Cache for $222.00 each and a $250
    > Motherboard
    >
    > VS
    >
    > One Athlon 64 3700+ 2.4GHz 1MB Cache for $519.00 and a $75.00 Mother
    > board
    >
    > Does 64 bits beat 2 processors?
    >
    > On Sat, 31 Jul 2004 13:25:43 -0400, JK <JK9821@netscape.net> wrote:
    >
    > >A better question to ask would be whether a dual processor system
    > >will outperform a single processor system of the same cost. That would
    > >probably mean using a faster processor than those used in the dual
    > >system, a 10,000 rpm hard drive in the single cpu system vs a 7,200
    > >rpm one in the dual processor system, and perhaps a better video card
    > >and more ram in the single processor system. A motherboard for dual
    > >processors is also more expensive than for a single one. If one wants
    > >to use Windows, XP professional needs to be used with dual processors,
    > >while XP home can be used with a single processor.
    > >
    > >PaulCsouls wrote:
    > >
    > >> Is there a general performance enhancement with dual processor boards
    > >> or is there only an advantage with certain applications?
    > >>
    > >> Paul
  10. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    It really depends on what you do with your PC. If you multitask a lot,
    especially running a CPU-intensive background job while working with an
    interactive application, then go with a dually. You'll get much better
    overall system response.

    If you run mostly background/batch jobs or a single CPU-intensive task
    such as gaming then a comparable single-CPU system will perform better
    and cost less.

    Another plus about a dually system is that it has a built-in damage
    control: a run-away process (assuming it is only single-threaded) in
    general won't kill your system.

    /kl


    PaulCsouls wrote:
    > Is there a general performance enhancement with dual processor boards
    > or is there only an advantage with certain applications?
    >
    > Paul
  11. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    As I said, it's a data point...

    FWIW, the desktop has a 32 MB (dedicated) graphics system, and the laptop
    has a 64 MB (shared RAM) system.

    Another benchmark (SI Sandra), which separates all the subsystems, confirms
    that in EVERY case the dual-CPU desktop is faster. The 2 (arithmetic and
    multi-media) CPU benchmarks were each 1.35 times faster on the dual 550,
    compared with the single 1.2 GHz; memory bandwidth was 3.7 x; and the file
    system (HD) was 2.4 x.

    So, even though the 2 CPUs were not able to process data much faster once
    the data got to them, they were served up that data much faster from RAM...


    "JK" <JK9821@netscape.net> wrote...
    > That is not a fair comparison, as the hard drive on a notebook is
    typically
    > much slower than the hard drive on a desktop. The graphics subsystem on
    > a desktop is also typically much faster than that of a notebook.
    >
    >> Win 2000 and XP Pro can allocate OS tasks among the processors as well as
    >> individual processes within applications. Also, CPU-intensive background
    >> apps will work without interfering with foreground tasks running on the
    >> other CPU. There will be even further enhancement with SMP-aware apps
    such
    >> as Photoshop (v5.5 and later).
    >>
    >> As a datapoint, my dual P-III/550 ran the Business Winstone twice as fast
    as
    >> my single P-III/1200 laptop.
  12. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    Thanks for the info. According to Tom's Hardware evaluation dual
    processors are not much better at gaming applications.
    I'm looking into a DOOM3 machine since I don't think my AMD K6-2
    450MHz will cut it. It's still running with case, power supply and
    monitor I bought with my 486, so I'm going to need the works. Anyway
    Dual processors sound like a neat thing to have but I don't think it's
    right for me. I'll definitely look at the Athlon 64s.

    Check out the DOOM3 benchmarks.

    http://www2.hardocp.com/article.html?art=NjQy

    Paul


    On Sat, 31 Jul 2004 22:49:46 -0400, JK <JK9821@netscape.net> wrote:

    >I expect the Athlon 64 3700+ to be much faster in most applications.
    >The Xeon is essentially a Pentium 4 that can be used in a dual
    >configuration. You might want to consider an Athlon 64 3800+
    >if you plan to do gaming or other high bandwith software, as it
    >has dual on chip memory controllers. Also keep in mind that
    >with a single Athlon 64 you can use Windows XP home, while a dual
    >Xeon system Would require Windows XP professional, so the
    >Athlon 64 3800+ would be more compare in price than the Athlon 64 3700+.
    >Even with 32 bit software, I would expect the Athlon 64 to come out
    >ahead with the vast majority of software. With 64 bit software, the
    >Athlon 64 performance would really be superb. Even with a 64 bit OS
    >and 32 bit software the Athlon 64 might perform much better in
    >many applications than its already great performance running 32
    >bit software with a 32 bit OS.
    >
    >PaulCsouls wrote:
    >
    >> Okay, I'll add some specifics.
    >>
    >> Two Intel Xeon 2.4GHz 533MHz FSB 512 Cache for $222.00 each and a $250
    >> Motherboard
    >>
    >> VS
    >>
    >> One Athlon 64 3700+ 2.4GHz 1MB Cache for $519.00 and a $75.00 Mother
    >> board
    >>
    >> Does 64 bits beat 2 processors?
    >>
    >> On Sat, 31 Jul 2004 13:25:43 -0400, JK <JK9821@netscape.net> wrote:
    >>
    >> >A better question to ask would be whether a dual processor system
    >> >will outperform a single processor system of the same cost. That would
    >> >probably mean using a faster processor than those used in the dual
    >> >system, a 10,000 rpm hard drive in the single cpu system vs a 7,200
    >> >rpm one in the dual processor system, and perhaps a better video card
    >> >and more ram in the single processor system. A motherboard for dual
    >> >processors is also more expensive than for a single one. If one wants
    >> >to use Windows, XP professional needs to be used with dual processors,
    >> >while XP home can be used with a single processor.
    >> >
    >> >PaulCsouls wrote:
    >> >
    >> >> Is there a general performance enhancement with dual processor boards
    >> >> or is there only an advantage with certain applications?
    >> >>
    >> >> Paul
  13. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    That Hardcop article is a review of video cards, not processors.
    Take a look at this review.

    http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2065&p=1


    PaulCsouls wrote:

    > Thanks for the info. According to Tom's Hardware evaluation dual
    > processors are not much better at gaming applications.
    > I'm looking into a DOOM3 machine since I don't think my AMD K6-2
    > 450MHz will cut it. It's still running with case, power supply and
    > monitor I bought with my 486, so I'm going to need the works. Anyway
    > Dual processors sound like a neat thing to have but I don't think it's
    > right for me. I'll definitely look at the Athlon 64s.
    >
    > Check out the DOOM3 benchmarks.
    >
    > http://www2.hardocp.com/article.html?art=NjQy
    >
    > Paul
    >
    > On Sat, 31 Jul 2004 22:49:46 -0400, JK <JK9821@netscape.net> wrote:
    >
    > >I expect the Athlon 64 3700+ to be much faster in most applications.
    > >The Xeon is essentially a Pentium 4 that can be used in a dual
    > >configuration. You might want to consider an Athlon 64 3800+
    > >if you plan to do gaming or other high bandwith software, as it
    > >has dual on chip memory controllers. Also keep in mind that
    > >with a single Athlon 64 you can use Windows XP home, while a dual
    > >Xeon system Would require Windows XP professional, so the
    > >Athlon 64 3800+ would be more compare in price than the Athlon 64 3700+.
    > >Even with 32 bit software, I would expect the Athlon 64 to come out
    > >ahead with the vast majority of software. With 64 bit software, the
    > >Athlon 64 performance would really be superb. Even with a 64 bit OS
    > >and 32 bit software the Athlon 64 might perform much better in
    > >many applications than its already great performance running 32
    > >bit software with a 32 bit OS.
    > >
    > >PaulCsouls wrote:
    > >
    > >> Okay, I'll add some specifics.
    > >>
    > >> Two Intel Xeon 2.4GHz 533MHz FSB 512 Cache for $222.00 each and a $250
    > >> Motherboard
    > >>
    > >> VS
    > >>
    > >> One Athlon 64 3700+ 2.4GHz 1MB Cache for $519.00 and a $75.00 Mother
    > >> board
    > >>
    > >> Does 64 bits beat 2 processors?
    > >>
    > >> On Sat, 31 Jul 2004 13:25:43 -0400, JK <JK9821@netscape.net> wrote:
    > >>
    > >> >A better question to ask would be whether a dual processor system
    > >> >will outperform a single processor system of the same cost. That would
    > >> >probably mean using a faster processor than those used in the dual
    > >> >system, a 10,000 rpm hard drive in the single cpu system vs a 7,200
    > >> >rpm one in the dual processor system, and perhaps a better video card
    > >> >and more ram in the single processor system. A motherboard for dual
    > >> >processors is also more expensive than for a single one. If one wants
    > >> >to use Windows, XP professional needs to be used with dual processors,
    > >> >while XP home can be used with a single processor.
    > >> >
    > >> >PaulCsouls wrote:
    > >> >
    > >> >> Is there a general performance enhancement with dual processor boards
    > >> >> or is there only an advantage with certain applications?
    > >> >>
    > >> >> Paul
  14. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    "David Maynard" <dNOTmayn@ev1.net> wrote...
    >
    > Regardless of which calculation one thinks is the best estimate it's
    rather
    > intuitive that two 550s, even summing to 1100, can't possibly be 'twice as
    > fast' as one 1200 of the same processor class unless something other than
    > the processors is at play.

    That could well be true for a system running a single app. However, once
    you get into multitasking, a dual-CPU system will be much more effective. I
    run database queries on my systems that hog an entire CPU for 15-60 seconds
    at a stretch. On the single-CPU machine, all other processes stop cold. On
    the dual, I work merrily along while the DB ferments in the background.

    Also, it is difficult to compare 2 systems -- 1 single-CPU and 1 dual-CPU --
    that are otherwise totally equal. Maybe I'll dust off my old 550, pull out
    a CPU, and compare scores...
  15. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    "JK" <JK9821@netscape.net> wrote...
    > I expect the Athlon 64 3700+ to be much faster in most applications.
    > The Xeon is essentially a Pentium 4 that can be used in a dual
    > configuration. You might want to consider an Athlon 64 3800+
    > if you plan to do gaming or other high bandwith software, as it
    > has dual on chip memory controllers.

    Another option is a dual Opteron setup. The Opteron 2xx series is the
    dual-capable version of the socket 939 Athlon 64.

    The Athlon 64 3500+ (2.2 GHz) costs about $350 at newegg, and the 3800+ (2.4
    GHz) is $640.

    The Opteron 240 (1.4 GHz) can be had for about $190 each, the 244 (1.8 GHz,
    at the "knee in the price curve right now) for $325 each, and the latest 250
    (2.4 GHz) goes for $825.

    For the gamer, the 3500+ may be the reasonable-cost answer. I like my dual
    246s...
  16. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    Looks like I should get a 939 socket chip that fits into my budget and
    that will leave me a reasonable upgrade path for a few years.


    On Sun, 01 Aug 2004 01:32:05 -0400, JK <JK9821@netscape.net> wrote:

    >That Hardcop article is a review of video cards, not processors.
    >Take a look at this review.
    >
    >http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2065&p=1
    >
    >
    >PaulCsouls wrote:
    >
    >> Thanks for the info. According to Tom's Hardware evaluation dual
    >> processors are not much better at gaming applications.
    >> I'm looking into a DOOM3 machine since I don't think my AMD K6-2
    >> 450MHz will cut it. It's still running with case, power supply and
    >> monitor I bought with my 486, so I'm going to need the works. Anyway
    >> Dual processors sound like a neat thing to have but I don't think it's
    >> right for me. I'll definitely look at the Athlon 64s.
    >>
    >> Check out the DOOM3 benchmarks.
    >>
    >> http://www2.hardocp.com/article.html?art=NjQy
    >>
    >> Paul
    >>
    >> On Sat, 31 Jul 2004 22:49:46 -0400, JK <JK9821@netscape.net> wrote:
    >>
    >> >I expect the Athlon 64 3700+ to be much faster in most applications.
    >> >The Xeon is essentially a Pentium 4 that can be used in a dual
    >> >configuration. You might want to consider an Athlon 64 3800+
    >> >if you plan to do gaming or other high bandwith software, as it
    >> >has dual on chip memory controllers. Also keep in mind that
    >> >with a single Athlon 64 you can use Windows XP home, while a dual
    >> >Xeon system Would require Windows XP professional, so the
    >> >Athlon 64 3800+ would be more compare in price than the Athlon 64 3700+.
    >> >Even with 32 bit software, I would expect the Athlon 64 to come out
    >> >ahead with the vast majority of software. With 64 bit software, the
    >> >Athlon 64 performance would really be superb. Even with a 64 bit OS
    >> >and 32 bit software the Athlon 64 might perform much better in
    >> >many applications than its already great performance running 32
    >> >bit software with a 32 bit OS.
    >> >
    >> >PaulCsouls wrote:
    >> >
    >> >> Okay, I'll add some specifics.
    >> >>
    >> >> Two Intel Xeon 2.4GHz 533MHz FSB 512 Cache for $222.00 each and a $250
    >> >> Motherboard
    >> >>
    >> >> VS
    >> >>
    >> >> One Athlon 64 3700+ 2.4GHz 1MB Cache for $519.00 and a $75.00 Mother
    >> >> board
    >> >>
    >> >> Does 64 bits beat 2 processors?
    >> >>
    >> >> On Sat, 31 Jul 2004 13:25:43 -0400, JK <JK9821@netscape.net> wrote:
    >> >>
    >> >> >A better question to ask would be whether a dual processor system
    >> >> >will outperform a single processor system of the same cost. That would
    >> >> >probably mean using a faster processor than those used in the dual
    >> >> >system, a 10,000 rpm hard drive in the single cpu system vs a 7,200
    >> >> >rpm one in the dual processor system, and perhaps a better video card
    >> >> >and more ram in the single processor system. A motherboard for dual
    >> >> >processors is also more expensive than for a single one. If one wants
    >> >> >to use Windows, XP professional needs to be used with dual processors,
    >> >> >while XP home can be used with a single processor.
    >> >> >
    >> >> >PaulCsouls wrote:
    >> >> >
    >> >> >> Is there a general performance enhancement with dual processor boards
    >> >> >> or is there only an advantage with certain applications?
    >> >> >>
    >> >> >> Paul
  17. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    ONLY with applications written to take advantage of dual processors, which
    are very few in number. Also the OS must be written to use dual CPU's.
    Windows XP Home, for instance, is not.

    --
    DaveW


    "PaulCsouls" <paulcsouls@worldnet.att.net> wrote in message
    news:kejng0945k3hiduasj57svcbv0a3vvkbq6@4ax.com...
    >
    > Is there a general performance enhancement with dual processor boards
    > or is there only an advantage with certain applications?
    >
    > Paul
  18. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    John R Weiss wrote:

    > "David Maynard" <dNOTmayn@ev1.net> wrote...
    >
    >>Regardless of which calculation one thinks is the best estimate it's
    >
    > rather
    >
    >>intuitive that two 550s, even summing to 1100, can't possibly be 'twice as
    >>fast' as one 1200 of the same processor class unless something other than
    >>the processors is at play.
    >
    >
    > That could well be true for a system running a single app.

    It's inherently true: 1100 can't possibly be bigger than 1200, much less
    'twice' as big.

    > However, once
    > you get into multitasking, a dual-CPU system will be much more effective.

    The comment was about 'speed', which I presumed meant processing power.
    'Effective' is another matter, depending on what you mean by it.

    > I
    > run database queries on my systems that hog an entire CPU for 15-60 seconds
    > at a stretch. On the single-CPU machine, all other processes stop cold.

    Well, they shouldn't 'stop cold' unless you've got priorities set to
    allocate CPU time exclusively to the database app.

    > On
    > the dual, I work merrily along while the DB ferments in the background.

    That is easily explained by postulating that the database app runs on only
    one processor so there's half of the system left 'idle' for your other apps
    to run in. That would be true regardless of what the combined 'speed' is
    and doesn't say anything about it.

    > Also, it is difficult to compare 2 systems -- 1 single-CPU and 1 dual-CPU --
    > that are otherwise totally equal. Maybe I'll dust off my old 550, pull out
    > a CPU, and compare scores...

    I don't understand why you say the comparison of otherwise equal systems is
    'difficult'.
  19. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    DaveW wrote:

    > ONLY with applications written to take advantage of dual processors, which
    > are very few in number.

    That is a common misconception derived from a premise that 'the one app' is
    the only measure of whether performance has increased, but there is never
    just 'the one app' running on a system.

    Even if 'the one app', which isn't SMP aware, is confined to operating on
    one processor, the second one frees it from being burdened by all the other
    apps and OS functions (lets not forget disk access, sound, video, etc.)
    from stealing time on the 'one' processor running 'the one app'.

    Given equivalent processors in the comparison, a dual processor system has
    twice the cache and twice the number of control registers for context
    switching, which is another reason why they feel more responsive.

    > Also the OS must be written to use dual CPU's.

    That, of course, is true.

    > Windows XP Home, for instance, is not.
    >


    "PaulCsouls" <paulcsouls@worldnet.att.net> wrote in message
    news:kejng0945k3hiduasj57svcbv0a3vvkbq6@4ax.com...

    >>
    >> Is there a general performance enhancement with dual processor boards
    >> or is there only an advantage with certain applications?
  20. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    On Sun, 01 Aug 2004 23:14:39 -0500, David Maynard wrote:
    > John R Weiss wrote:
    >> "David Maynard" <dNOTmayn@ev1.net> wrote...
    >>>Regardless of which calculation one thinks is the best estimate it's
    >> rather intuitive that two 550s, even summing to 1100, can't possibly be
    >> 'twice as fast' as one 1200 of the same processor class unless
    >> something other than the processors is at play.
    >>
    >> That could well be true for a system running a single app.
    >
    > It's inherently true: 1100 can't possibly be bigger than 1200, much less
    > 'twice' as big.
    >
    >> However, once
    >> you get into multitasking, a dual-CPU system will be much more
    >> effective.
    >
    > The comment was about 'speed', which I presumed meant processing power.
    > 'Effective' is another matter, depending on what you mean by it.
    >
    >> I run database queries on my systems that hog an entire CPU for 15-60
    >> seconds at a stretch. On the single-CPU machine, all other processes
    >> stop cold.
    >
    > Well, they shouldn't 'stop cold' unless you've got priorities set to
    > allocate CPU time exclusively to the database app.

    Depends on the "O/S". I remember having that experience when running
    big/long Access97 queries on Windows98 at a client site. Access is nice.
    Windows98 blows chunks. That "cooperative multitasking" b.s. (dunno if
    they've finally got rid of it? no, I guess then it wouldn't "act like
    windows", would it?) was quite probably at fault. In my case, I had
    written some queries using VBA, so that I could do special programmed
    selections, and processing. Turned out that while the VBA loop was
    running, nothing else would get any CPU. I had to put in "breaks" into the
    code: e.g. count 100 iterations in the loop and make special system calls
    to "voluntarily give up" the CPU to anyone that might want it. I'm used to
    preemptive multi-tasking and time-slicing schedulers in "real" O/S, so
    this was really/specially annoying. To actually have to write in kludges
    to make multitasking work is an abomination! BTW, while I was kludging I
    put in some "progress indicators". They also helped, since the queries
    were slow/long and sometimes you wondered if it had crashed (again?).

    >> On the dual, I work merrily along while the DB ferments in the
    >> background.
    >
    > That is easily explained by postulating that the database app runs on
    > only one processor so there's half of the system left 'idle' for your
    > other apps to run in. That would be true regardless of what the combined
    > 'speed' is and doesn't say anything about it.
    >
    >> Also, it is difficult to compare 2 systems -- 1 single-CPU and 1
    >> dual-CPU -- that are otherwise totally equal. Maybe I'll dust off my
    >> old 550, pull out a CPU, and compare scores...
    >
    > I don't understand why you say the comparison of otherwise equal systems
    > is 'difficult'.

    Yeah. I generally favor multiprocessor systems for that reason. There are
    more CPUs to share the load, and there's more likely one "free" to handle
    any new work or event.

    BTW, you cannot always linearly generalize viz. clock rates, etc. I had a
    case where a quad-CPU system seemed to not perform much better (if at all)
    than a dual-CPU on the same mobo. The quad CPUs were actually higher clock
    rate (but different internal architecture, tho same instruction set), but
    smaller cache. I think it was a combination of cache starvation and
    perhaps also memory bus choking that limited performance.

    p.s. These days I run Solaris and Linux and I'm much happier. YMMV

    --
    Juhan Leemet
    Logicognosis, Inc.
  21. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    Juhan Leemet wrote:

    > On Sun, 01 Aug 2004 23:14:39 -0500, David Maynard wrote:
    >
    >>John R Weiss wrote:
    >>
    >>>"David Maynard" <dNOTmayn@ev1.net> wrote...
    >>>
    >>>>Regardless of which calculation one thinks is the best estimate it's
    >>>
    >>>rather intuitive that two 550s, even summing to 1100, can't possibly be
    >>>'twice as fast' as one 1200 of the same processor class unless
    >>>something other than the processors is at play.
    >>>
    >>>That could well be true for a system running a single app.
    >>
    >>It's inherently true: 1100 can't possibly be bigger than 1200, much less
    >>'twice' as big.
    >>
    >>
    >>> However, once
    >>>you get into multitasking, a dual-CPU system will be much more
    >>>effective.
    >>
    >>The comment was about 'speed', which I presumed meant processing power.
    >>'Effective' is another matter, depending on what you mean by it.
    >>
    >>
    >>> I run database queries on my systems that hog an entire CPU for 15-60
    >>>seconds at a stretch. On the single-CPU machine, all other processes
    >>>stop cold.
    >>
    >>Well, they shouldn't 'stop cold' unless you've got priorities set to
    >>allocate CPU time exclusively to the database app.
    >
    >
    > Depends on the "O/S". I remember having that experience when running
    > big/long Access97 queries on Windows98 at a client site. Access is nice.
    > Windows98 blows chunks. That "cooperative multitasking" b.s. (dunno if
    > they've finally got rid of it? no, I guess then it wouldn't "act like
    > windows", would it?) was quite probably at fault. In my case, I had
    > written some queries using VBA, so that I could do special programmed
    > selections, and processing. Turned out that while the VBA loop was
    > running, nothing else would get any CPU. I had to put in "breaks" into the
    > code: e.g. count 100 iterations in the loop and make special system calls
    > to "voluntarily give up" the CPU to anyone that might want it. I'm used to
    > preemptive multi-tasking and time-slicing schedulers in "real" O/S, so
    > this was really/specially annoying. To actually have to write in kludges
    > to make multitasking work is an abomination! BTW, while I was kludging I
    > put in some "progress indicators". They also helped, since the queries
    > were slow/long and sometimes you wondered if it had crashed (again?).

    Well, I had the impression he was using a Win2K/XP system. The Win9x series
    is completely different.


    >>> On the dual, I work merrily along while the DB ferments in the
    >>> background.
    >>
    >>That is easily explained by postulating that the database app runs on
    >>only one processor so there's half of the system left 'idle' for your
    >>other apps to run in. That would be true regardless of what the combined
    >>'speed' is and doesn't say anything about it.
    >>
    >>
    >>>Also, it is difficult to compare 2 systems -- 1 single-CPU and 1
    >>>dual-CPU -- that are otherwise totally equal. Maybe I'll dust off my
    >>>old 550, pull out a CPU, and compare scores...
    >>
    >>I don't understand why you say the comparison of otherwise equal systems
    >>is 'difficult'.
    >
    >
    > Yeah. I generally favor multiprocessor systems for that reason. There are
    > more CPUs to share the load, and there's more likely one "free" to handle
    > any new work or event.
    >
    > BTW, you cannot always linearly generalize viz. clock rates, etc. I had a
    > case where a quad-CPU system seemed to not perform much better (if at all)
    > than a dual-CPU on the same mobo. The quad CPUs were actually higher clock
    > rate (but different internal architecture, tho same instruction set), but
    > smaller cache. I think it was a combination of cache starvation and
    > perhaps also memory bus choking that limited performance.

    Yes. That's why I said processors of the same class.

    >
    > p.s. These days I run Solaris and Linux and I'm much happier. YMMV
    >
  22. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    Not true when multitasking!

    Win NT4 (to a lesser degree), 2000, and XP Pro all have code that allows
    apps/processes to be intelligently assigned to the best available CPU. For
    example, a database query can hog an entire CPU in the background, and you
    can use another app in the foreground on the other CPU.

    "DaveW" <none@zero.org> wrote...
    > ONLY with applications written to take advantage of dual processors, which
    > are very few in number. Also the OS must be written to use dual CPU's.
    > Windows XP Home, for instance, is not.

    >> Is there a general performance enhancement with dual processor boards
    >> or is there only an advantage with certain applications?
  23. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    "David Maynard" <dNOTmayn@ev1.net> wrote...
    >
    > It's inherently true: 1100 can't possibly be bigger than 1200, much less
    > 'twice' as big.

    If you are considering the CPU only, that's true. If you consider the
    entire system, it may or may not be true.


    >> However, once
    >> you get into multitasking, a dual-CPU system will be much more effective.
    >
    > The comment was about 'speed', which I presumed meant processing power.
    > 'Effective' is another matter, depending on what you mean by it.

    "Effective" is speed/ease of accomplishing work/tasks. If you cannot
    perform a second task at all because another is hogging CPU time, the system
    is not effective at all in performing the second task.
  24. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    John R Weiss wrote:

    > "David Maynard" <dNOTmayn@ev1.net> wrote...
    >
    >>It's inherently true: 1100 can't possibly be bigger than 1200, much less
    >>'twice' as big.
    >
    >
    > If you are considering the CPU only, that's true. If you consider the
    > entire system, it may or may not be true.

    He wasn't making a 'system' comparison. He was making a statement about
    dual 550 processors vs a 1200 processor and if the rest of the system is
    dramatically different then it isn't be a valid 'processor' comparison;
    which was the problem with his where the disparity between a true AGP card
    vs built in shared memory display corrupts the results.

    Just as it wouldn't be valid to compare how fast Word2 for DOS comes up on
    a PIII-933 vs WordXP on an XP 1800+ running WinXP and claim the PIII 933
    was 'twice as fast' as the AMD XP 1800+.

    >>> However, once
    >>>you get into multitasking, a dual-CPU system will be much more effective.
    >>
    >>The comment was about 'speed', which I presumed meant processing power.
    >>'Effective' is another matter, depending on what you mean by it.
    >
    >
    > "Effective" is speed/ease of accomplishing work/tasks. If you cannot
    > perform a second task at all because another is hogging CPU time, the system
    > is not effective at all in performing the second task.

    That is certainly one way of looking at it but 'effective' depends on what
    one wants to do. If, for example, the purpose is to perform that one task
    as fast as possible then a dual system is not as 'effective' as a single.

    However, as I said, the original comment was about 'processing speed' and
    that two 550s were 'twice as fast' as a single 1200 and I still maintain
    that is simply not true, all else being equal.

    It may 'feel' more keyboard 'responsive' or it may meet your particular
    opinion of 'more effective' but the dual processors in the comparison
    aren't 'twice as fast' as the single.
  25. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    On Sat, 31 Jul 2004 16:55:26 GMT, PaulCsouls <paulcsouls@worldnet.att.net>
    wrote:

    >
    >Is there a general performance enhancement with dual processor boards
    >or is there only an advantage with certain applications?
    >
    >Paul

    Hi,

    Good question. Bringing lots of great answers. I always liked this link. It's
    old, in computer years, but I like the concepts.

    http://arstechnica.com/cpu/3q99/smp/smp-1.html

    Steve
    My real email address is dealsgalore[A-T]earthlink.net

    www.cheap-land.com
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