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Science Forum Index » Electronics - Design Forum » OT Dual core CPUs versus faster single core CPUs?
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| John Doe |
Posted: Thu May 01, 2008 3:05 pm |
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Not trying to decide which is better for everybody. Just interested
in the difference between multiple core CPUs and faster single core
CPUs.
Are there any mainstream applications that would benefit from one
and the other?
My wild guess. Continuous multitasking versus intermittent bursts
(if the bursts usually do not coincide). But I don't know of any
applications to example that.
Thanks. |
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| hrh1818 |
Posted: Thu May 01, 2008 3:08 pm |
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On May 1, 3:05 pm, John Doe <j...@usenetlove.invalid> wrote:
Quote: Not trying to decide which is better for everybody. Just interested
in the difference between multiple core CPUs and faster single core
CPUs.
Are there any mainstream applications that would benefit from one
and the other?
My wild guess. Continuous multitasking versus intermittent bursts
(if the bursts usually do not coincide). But I don't know of any
applications to example that.
Thanks.
Matlab can benefit from multiple cores but with LTspice being single
threaded you get the most bang for your buck by going to the fastest
CPU you can afford.
Howard |
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| Rich Webb |
Posted: Thu May 01, 2008 3:20 pm |
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On Thu, 01 May 2008 20:05:51 GMT, John Doe <jdoe@usenetlove.invalid>
wrote:
Quote:
Not trying to decide which is better for everybody. Just interested
in the difference between multiple core CPUs and faster single core
CPUs.
Are there any mainstream applications that would benefit from one
and the other?
I do run into cases where an app totally pegs one of the cores,
sometimes due to a crash, sometimes due to a not particularly well
written application that is a resource hog. Regardless, even with one
core completely occupied, the other is free to respond to user and O/S
events whereas a single core setup, even a very fast one, would
probably be quite unresponsive and might require hitting The Big Red
Switch (or the equivalent nowadays) to regain control.
--
Rich Webb Norfolk, VA |
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| Dave Platt |
Posted: Thu May 01, 2008 4:18 pm |
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Quote: Not trying to decide which is better for everybody. Just interested
in the difference between multiple core CPUs and faster single core
CPUs.
My understanding is that these days, it's possible to get more
computing power per watt using a multicore approach. Going to higher
and higher speeds (per core) requires the use of a smaller and smaller
feature size on the chip, and this can increase static power losses.
Lower operating voltages are required to keep from popping through the
thinner insulating layers on the chip, and this generally means that
higher currents are required, which means that I^2*R losses go up and
overall power efficiency goes down.
Using a somewhat lower-technology silicon process with lower losses,
and replicating it several times, can yield the same amount of
computing power at a lower level of energy consumption.
For desktop consumers this may not be all that significant an issue.
For server farms, where the electric bill can be a major portion of
the total expense over time, it can make a big difference. For laptop
owners, it may extend battery run-time or reduce battery weight
significantly.
There would be additional benefits if the chip (or the ACPI BIOS or
the operating system) can halt or even power down the extra core(s)
except when their services are needed.
Quote: Are there any mainstream applications that would benefit from one
and the other?
Any application whose processing can be partitioned, and run in
phases, is a candidate. Image processing (e.g. tweaking photos or
artwork) or audio digital signal processing (e.g. running streaming
MP3 or Ogg Vorbis encoders for a Shoutcast/Icecast stream server)
would be candidates. Cryptographic acceleration (e.g. SSL
connections) might be another.
I think that a significant benefit can arise if the code being run on
any given processor, will fit well into a single core's instruction
cache. If the OS is smart enough to "lock" the thread in question
into a single core, you can avoid a whole lot of icache misses and
reloading which would occur on a single-core processor, and this can
allow the core to run at closer to its theoretical limit.
--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads! |
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| John Doe |
Posted: Thu May 01, 2008 4:33 pm |
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dplatt@radagast.org (Dave Platt) wrote:
Quote: Just interested in the difference between multiple core CPUs and
faster single core CPUs.
My understanding is that these days, it's possible to get more
computing power per watt using a multicore approach. Going to
higher and higher speeds (per core) requires the use of a smaller
and smaller feature size on the chip, and this can increase static
power losses. Lower operating voltages are required to keep from
popping through the thinner insulating layers on the chip, and
this generally means that higher currents are required, which
means that I^2*R losses go up and overall power efficiency goes
down.
Using a somewhat lower-technology silicon process with lower
losses, and replicating it several times, can yield the same
amount of computing power ...
If you're talking about replicating the same speed, yes that's very
easy to believe. |
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| PeterD |
Posted: Thu May 01, 2008 4:41 pm |
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Guest
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On Thu, 01 May 2008 20:05:51 GMT, John Doe <jdoe@usenetlove.invalid>
wrote:
Quote:
Not trying to decide which is better for everybody. Just interested
in the difference between multiple core CPUs and faster single core
CPUs.
Are there any mainstream applications that would benefit from one
and the other?
My wild guess. Continuous multitasking versus intermittent bursts
(if the bursts usually do not coincide). But I don't know of any
applications to example that.
Thanks.
It is not a simple comparison, many different factors to consider.
But, overall, it is the total MIPS/MFLOPS that really count. |
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| John Doe |
Posted: Thu May 01, 2008 6:12 pm |
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PeterD <peter2@hipson.net> wrote:
Quote: It is not a simple comparison,
That's why I'm asking here... as caretakers of the universe, you all
know everything.
Quote: many different factors to consider. But, overall, it is the total
MIPS/MFLOPS that really count. |
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| John Larkin |
Posted: Thu May 01, 2008 7:28 pm |
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On Thu, 01 May 2008 20:05:51 GMT, John Doe <jdoe@usenetlove.invalid>
wrote:
Quote:
Not trying to decide which is better for everybody. Just interested
in the difference between multiple core CPUs and faster single core
CPUs.
Are there any mainstream applications that would benefit from one
and the other?
My wild guess. Continuous multitasking versus intermittent bursts
(if the bursts usually do not coincide). But I don't know of any
applications to example that.
Thanks.
Dual core is just a hint of what's happening. There are already chips
with hundreds of cores.
Most people don't need huge number-crunching ability; they need
reliable, low-power computing. If current programming methods are
extended into multicore - parallelism, virtualization - we'll just
compound the mess that computing is today.
The real use for multiple cores will to be to assign one function per
core. One would be the OS kernal, and only that, and would be entirely
protected from other processes. Other cores could be assigned to be
specific device drivers, file managers, TCP/IP socket managers, things
like that. Then one core could be assigned to each application process
or thread. Only a few cores need floating-point horespower, which
might be hardware shared. Power down idle cores. Voila, no context
switching, no memory corruption, and an OS that never crashes.
Microsoft won't like it at all.
John |
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| Tam |
Posted: Thu May 01, 2008 7:56 pm |
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"John Doe" <jdoe@usenetlove.invalid> wrote in message
news:zopSj.12802$GE1.3351@nlpi061.nbdc.sbc.com...
Quote:
Not trying to decide which is better for everybody. Just interested
in the difference between multiple core CPUs and faster single core
CPUs.
Are there any mainstream applications that would benefit from one
and the other?
My wild guess. Continuous multitasking versus intermittent bursts
(if the bursts usually do not coincide). But I don't know of any
applications to example that.
Thanks.
Writers for various computer magazines seem to agree that what you want is
the fastest Core2 Duo that you can afford. I have a 2 GHz Core 2 Duo on the
laptop that I am writing this on. It is slightly slower (~10%) on mumber
crunching than the 3.4GHz (equivalent) AMD single core machine upstairs. The
laptop runs Vista, the AMD runs XPsp2. Both have 2G RAM. I think the fastest
C2D is around 2.8 GHz.
Tam |
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| Joerg |
Posted: Thu May 01, 2008 8:36 pm |
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John Larkin wrote:
Quote: On Thu, 01 May 2008 20:05:51 GMT, John Doe <jdoe@usenetlove.invalid
wrote:
Not trying to decide which is better for everybody. Just interested
in the difference between multiple core CPUs and faster single core
CPUs.
Are there any mainstream applications that would benefit from one
and the other?
My wild guess. Continuous multitasking versus intermittent bursts
(if the bursts usually do not coincide). But I don't know of any
applications to example that.
Thanks.
Dual core is just a hint of what's happening. There are already chips
with hundreds of cores.
Most people don't need huge number-crunching ability; they need
reliable, low-power computing. If current programming methods are
extended into multicore - parallelism, virtualization - we'll just
compound the mess that computing is today.
The real use for multiple cores will to be to assign one function per
core. One would be the OS kernal, and only that, and would be entirely
protected from other processes. Other cores could be assigned to be
specific device drivers, file managers, TCP/IP socket managers, things
like that. Then one core could be assigned to each application process
or thread. Only a few cores need floating-point horespower, which
might be hardware shared. Power down idle cores. Voila, no context
switching, no memory corruption, and an OS that never crashes.
Microsoft won't like it at all.
Does anyone know what the difference is between an Intel Dual-Core and
the Core 2 Duo? Is one 32bit and the other 64?
This here machine has a dual core and it really shows up as two separate
CPUs in the control panel.
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM. |
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| John Doe |
Posted: Thu May 01, 2008 9:01 pm |
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Joerg <notthisjoergsch@removethispacbell.net> wrote:
Quote: Does anyone know what the difference is between an Intel Dual-Core
and the Core 2 Duo?
I've read but haven't researched that the Core 2 Duo is 2-4 times
faster than an equivalent Dual-Core. They said it manages CPU usage
much better. I look forward to seeing multiple CPU core usage graphs
in Performance Monitor, if Windows XP will do that. |
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| Jamie |
Posted: Thu May 01, 2008 9:15 pm |
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John Doe wrote:
Quote: Joerg <notthisjoergsch@removethispacbell.net> wrote:
Does anyone know what the difference is between an Intel Dual-Core
and the Core 2 Duo?
I've read but haven't researched that the Core 2 Duo is 2-4 times
faster than an equivalent Dual-Core. They said it manages CPU usage
much better. I look forward to seeing multiple CPU core usage graphs
in Performance Monitor, if Windows XP will do that.
MS has doomed it self..
they have removed XP from the stores as of today unless they changed
their mind since then.
http://webpages.charter.net/jamie_5" |
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| John Doe |
Posted: Fri May 02, 2008 12:22 am |
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dplatt@radagast.org (Dave Platt) wrote:
Quote: My understanding is that these days, it's possible to get more
computing power per watt using a multicore approach. Going to
higher and higher speeds (per core) requires the use of a smaller
and smaller feature size on the chip, and this can increase static
power losses. Lower operating voltages are required to keep from
popping through the thinner insulating layers on the chip, and
this generally means that higher currents are required, which
means that I^2*R losses go up and overall power efficiency goes
down.
I see, same reason for high-voltage power lines. Does the lower
voltage also have anything to do with the fact electrons travel
shorter distances? Thanks.
--
Thanks to the replies. |
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