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why win limits CPU usage to 50%?

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Anonymous
a b à CPUs
August 2, 2005 8:07:47 AM

Archived from groups: microsoft.public.windowsxp.perform_maintain (More info?)

In 2 computers with Pentium 4 540 3.2Ghz / 1GB RAM and P4 3GHz / 2GB RAM
the other, with Windows XP Sp2 in both computers, any process (I probe
Rhino and PET) uses only 50% of CPU in any priority (I set normal and
high). In my computer (Athlon XP 2000 with the same OS) I don't have
this problem.


--
xavmdq

More about : win limits cpu usage

Anonymous
a b à CPUs
August 2, 2005 12:19:56 PM

Archived from groups: microsoft.public.windowsxp.perform_maintain (More info?)

xavmdq wrote:
> In 2 computers with Pentium 4 540 3.2Ghz / 1GB RAM and P4 3GHz / 2GB
> RAM the other, with Windows XP Sp2 in both computers, any process (I
> probe Rhino and PET) uses only 50% of CPU in any priority (I set
> normal and high). In my computer (Athlon XP 2000 with the same OS) I
> don't have this problem.

Seems to be unique to you.
I frequently get over 50% of CPU usage on a CPU, dependent on the
application.

Get "HeavyLoad" from here and try running it..
http://www.jam-software.com/freeware/index.shtml

--
Shenan Stanley
MS-MVP
--
How To Ask Questions The Smart Way
http://www.catb.org/~esr/faqs/smart-questions.html
Anonymous
a b à CPUs
August 2, 2005 3:55:19 PM

Archived from groups: microsoft.public.windowsxp.perform_maintain (More info?)

xavmdq wrote:
> In 2 computers with Pentium 4 540 3.2Ghz / 1GB RAM and P4 3GHz / 2GB RAM
> the other, with Windows XP Sp2 in both computers, any process (I probe
> Rhino and PET) uses only 50% of CPU in any priority (I set normal and
> high).

I suppose you've dismissed the idea that your CPUs are so powerful that
they perform any task without exerting themselves beyond 50%? :) 
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Anonymous
a b à CPUs
August 5, 2005 6:19:35 AM

Archived from groups: microsoft.public.windowsxp.perform_maintain (More info?)

Michael W. Ryder wrote:

> The 540 is a hyperthreading processor so most single jobs will only use
> half of the CPU's power. I only use 50% on my 3.4 GHz processor with
> most jobs. But if I am running a large data import in Excel and a large
> data conversion in a DOS program at the same time then the processor
> goes to 100%.

So are we saying that with a HT processor, if we are running only one
task, we can only get 50% of available processing power? Surely that
would be a deficiency in too many circumstances. Is this really the way
it works?
Anonymous
a b à CPUs
August 5, 2005 12:03:34 PM

Archived from groups: microsoft.public.windowsxp.perform_maintain (More info?)

xavmdq wrote:
> In 2 computers with Pentium 4 540 3.2Ghz / 1GB RAM and P4 3GHz / 2GB RAM
> the other, with Windows XP Sp2 in both computers, any process (I probe
> Rhino and PET) uses only 50% of CPU in any priority (I set normal and
> high). In my computer (Athlon XP 2000 with the same OS) I don't have
> this problem.
>
>
The 540 is a hyperthreading processor so most single jobs will only use
half of the CPU's power. I only use 50% on my 3.4 GHz processor with
most jobs. But if I am running a large data import in Excel and a large
data conversion in a DOS program at the same time then the processor
goes to 100%.
Anonymous
a b à CPUs
August 5, 2005 3:42:29 PM

Archived from groups: microsoft.public.windowsxp.perform_maintain (More info?)

Dr Teeth wrote:
> On 5 Aug 2005 02:19:35 -0700, "bxf" <bill@topman.net> wrote:
>
> >So are we saying that with a HT processor, if we are running only one
> >task, we can only get 50% of available processing power?
>
> But that is 100% of one (of two) CPUs (albeit virtual ones).

I'd done just a bit of reading on the subject of HT in the past, and I
understood that, given the right mix of work, a HT processor can
slightly outperform a non-HT one. I cannot translate this to mean that
each CPU of a HT processor is the equivalent of a comparable speed
non-HT processor.

So, if you mean to say that 100% of one (of two) is the equivalent of
100% of one (of one), that would conflict with the above. On the other
hand, if a HT processor can only use half the total power when running
only a single task, then the processor is being under-utilized much of
the time, and I'd find that hard to believe.

Ths does not mean that there isn't some anomaly in the reported CPU
usage for HT processors. But then again, the OP says 50% all the time -
no more, no less.
Anonymous
a b à CPUs
August 5, 2005 8:25:07 PM

Archived from groups: microsoft.public.windowsxp.perform_maintain (More info?)

On 5 Aug 2005 02:19:35 -0700, "bxf" <bill@topman.net> wrote:

>So are we saying that with a HT processor, if we are running only one
>task, we can only get 50% of available processing power?

But that is 100% of one (of two) CPUs (albeit virtual ones).

--
Cheers,

Guy

** Stress - the condition brought about by having to
** resist the temptation to beat the living daylights
** out of someone who richly deserves it.
Anonymous
a b à CPUs
August 5, 2005 10:24:54 PM

Archived from groups: microsoft.public.windowsxp.perform_maintain (More info?)

bxf wrote:
> Michael W. Ryder wrote:
>
>
>>The 540 is a hyperthreading processor so most single jobs will only use
>>half of the CPU's power. I only use 50% on my 3.4 GHz processor with
>>most jobs. But if I am running a large data import in Excel and a large
>>data conversion in a DOS program at the same time then the processor
>>goes to 100%.
>
>
> So are we saying that with a HT processor, if we are running only one
> task, we can only get 50% of available processing power? Surely that
> would be a deficiency in too many circumstances. Is this really the way
> it works?
>

The advantage in Hyperthreading is that with my Northwood P4 I could
only run one of the jobs at a time. Now I can run both of them at the
same time without any apparent difference in run time. This can save a
lot of time if you have multiple jobs to run together.
Anonymous
a b à CPUs
August 6, 2005 2:19:30 PM

Archived from groups: microsoft.public.windowsxp.perform_maintain (More info?)

Hi,

Hyper-Threading allows the processor to execute 2 different software threads
simultaneously on each physical processor. As i see it, the processor executes what's
delivered to it. And i found nothing that suggests that the processor behaves any
differently in terms of % weather it receives single or multiple threads. The "How
Hyper-Threading Technology Works" demo explains the process nicely.

Intel® Hyper-Threading Technology (HT Technology) Demo for Servers
http://www.intel.com/business/bss/products/hyperthreadi...

Hyper-Threading Technology
http://www.intel.com/technology/hyperthread/

--
Regards,
Bert Kinney MS-MVP Shell/User
http://bertk.mvps.org

bxf wrote:
> Michael W. Ryder wrote:
>
>> The 540 is a hyperthreading processor so most single
>> jobs will only use half of the CPU's power. I only use
>> 50% on my 3.4 GHz processor with most jobs. But if I am
>> running a large data import in Excel and a large data
>> conversion in a DOS program at the same time then the
>> processor goes to 100%.
>
> So are we saying that with a HT processor, if we are
> running only one task, we can only get 50% of available
> processing power? Surely that would be a deficiency in
> too many circumstances. Is this really the way it works?
Anonymous
a b à CPUs
May 27, 2010 11:55:37 AM

I have 2 pcs similar configuration (both with Core2 Duo and XP SP2). In one Excel uses only 50% of processor, in another Excel uses only 100% of processor. That's the question!!! :o 
July 22, 2011 2:16:17 PM

I have the same problem.
2 machines both WinXP SP3 both intel based processors P4 2.8Ghz 4G RAM even same motherboard.
[One with latest updates, one not].

- Running the same application (heavy duty task in .NET writing data to .accdb file after crawling the web)
- Setting priority to Realtime (I've tried Idle too since the machines does nothing else).

One machine - never exceed 50% CPU (the other 50% is System Idle Process most of the time).
the other - uses 100% CPU (during that time it is very hard to work on the machine - but it is great for me cause it meant to work in non attended mode).

the second machine outpreform and finishes the heavy task segnificantly faster than the 50% machine.

I fail to realize the difference and how to cause the lazy 50% machine use max CPU time
(and save me time and energy by working in short burst and sleep).

I'm about to give up on XP and turn to Win Server 2008 or Win7 I'm sure it will be more friendly to this SW.

I would love to hear if there is anyone here knowing where is the damn button/key/value/settings/configuration/jumper
making this difference.
!