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CPU Voltage Measurements

 
 
Jack R
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      06-25-2007, 08:54 PM
What utility/program do you folks use to measure the CPU core voltage?
I've been trying an assortment and getting varying results, so I don't know
what to trust, and which to use as a guide for OC settings.

I get:

CPU-Z 1.40: 1.213V (under stress testing, jumps to 1.440V and back)
CoreTemp 0.95: 1.3250V
BIOS: 1.48V
PCProbeII, SpeedFan and FreshDiag: 1.52V

This is on an ASUS P5N-E SLI mb, with an Intel C2D E6600, set at +.100 in
the BIOS.

Thanks for help and suggestions,

Jack R.

(Currently running at 3.3GHZ, mem at 856MHz, video +15% OC)


 
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M. R. Carleer
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Posts: n/a
 
      06-26-2007, 02:10 PM
The E6600 has a feature by which it saves power when idle. It does this in
two ways that I know of: lowering the internal clock multiplier (from x9 to
x6) and lowering the requested VCore by about 0.2V.
This explains what you read in CPU-Z, unless you specifically disabled the
power saving feature in the BIOS.
As for the other progs, I don't use them so cannot comment (except for
speedfan which I use only to measure temps).

"Jack R" <(E-Mail Removed)> wrote in message
news:ZXVfi.32$(E-Mail Removed)...
> What utility/program do you folks use to measure the CPU core voltage?
> I've been trying an assortment and getting varying results, so I don't

know
> what to trust, and which to use as a guide for OC settings.
>
> I get:
>
> CPU-Z 1.40: 1.213V (under stress testing, jumps to 1.440V and back)
> CoreTemp 0.95: 1.3250V
> BIOS: 1.48V
> PCProbeII, SpeedFan and FreshDiag: 1.52V
>
> This is on an ASUS P5N-E SLI mb, with an Intel C2D E6600, set at +.100 in
> the BIOS.
>
> Thanks for help and suggestions,
>
> Jack R.
>
> (Currently running at 3.3GHZ, mem at 856MHz, video +15% OC)
>
>



 
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Jack R
Guest
Posts: n/a
 
      06-26-2007, 04:41 PM
>
> "Jack R" <(E-Mail Removed)> wrote in message
> news:ZXVfi.32$(E-Mail Removed)...
>> What utility/program do you folks use to measure the CPU core voltage?
>> I've been trying an assortment and getting varying results, so I don't

> know
>> what to trust, and which to use as a guide for OC settings.
>>
>> I get:
>>
>> CPU-Z 1.40: 1.213V (under stress testing, jumps to 1.440V and back)
>> CoreTemp 0.95: 1.3250V
>> BIOS: 1.48V
>> PCProbeII, SpeedFan and FreshDiag: 1.52V
>>
>> This is on an ASUS P5N-E SLI mb, with an Intel C2D E6600, set at +.100 in
>> the BIOS.
>>
>> Thanks for help and suggestions,
>>
>> Jack R.
>>
>> (Currently running at 3.3GHZ, mem at 856MHz, video +15% OC)
>>
>>

> "M. R. Carleer" <(E-Mail Removed)> wrote in message
> news:f5r6o7$908$(E-Mail Removed)...
> The E6600 has a feature by which it saves power when idle. It does this in
> two ways that I know of: lowering the internal clock multiplier (from x9
> to
> x6) and lowering the requested VCore by about 0.2V.
> This explains what you read in CPU-Z, unless you specifically disabled the
> power saving feature in the BIOS.
> As for the other progs, I don't use them so cannot comment (except for
> speedfan which I use only to measure temps).


Thanks for your reply.
I have all of the power saving features turned off.
My guess is the variation is just measurement 'noise', not actual voltage
variation.
It only occurs during 100% stress tests, not in any static situation.
Jack R.

 
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Michel R. Carleer
Guest
Posts: n/a
 
      06-26-2007, 04:57 PM
Well, in my case, I can tell you that the ~0.1V variation has nothing to do
with noise. It is indeed clearly due to the C2D going into idle power saving
mode:
- As long as I do nothing with my PC, the voltage is around 1.14 +/- 0.01 V.
As soon as I start using the CPU heavily (Orthos or some other intensive
prog), the voltage raises to 1.22 +/- 0.01 V.
- It happens completely in sync with the clock multiplier going from x 6 to
x 9. And back when going back to idle.
OK, this is all with an Asus P5W DH mobo.
Speedfan gives me the exact same figures.

"Jack R" <(E-Mail Removed)> wrote in message
news:Xkbgi.11$%(E-Mail Removed)...
> >
>> "Jack R" <(E-Mail Removed)> wrote in message
>> news:ZXVfi.32$(E-Mail Removed)...
>>> What utility/program do you folks use to measure the CPU core voltage?
>>> I've been trying an assortment and getting varying results, so I don't

>> know
>>> what to trust, and which to use as a guide for OC settings.
>>>
>>> I get:
>>>
>>> CPU-Z 1.40: 1.213V (under stress testing, jumps to 1.440V and back)
>>> CoreTemp 0.95: 1.3250V
>>> BIOS: 1.48V
>>> PCProbeII, SpeedFan and FreshDiag: 1.52V
>>>
>>> This is on an ASUS P5N-E SLI mb, with an Intel C2D E6600, set at +.100
>>> in
>>> the BIOS.
>>>
>>> Thanks for help and suggestions,
>>>
>>> Jack R.
>>>
>>> (Currently running at 3.3GHZ, mem at 856MHz, video +15% OC)
>>>
>>>

>> "M. R. Carleer" <(E-Mail Removed)> wrote in message
>> news:f5r6o7$908$(E-Mail Removed)...
>> The E6600 has a feature by which it saves power when idle. It does this
>> in
>> two ways that I know of: lowering the internal clock multiplier (from x9
>> to
>> x6) and lowering the requested VCore by about 0.2V.
>> This explains what you read in CPU-Z, unless you specifically disabled
>> the
>> power saving feature in the BIOS.
>> As for the other progs, I don't use them so cannot comment (except for
>> speedfan which I use only to measure temps).

>
> Thanks for your reply.
> I have all of the power saving features turned off.
> My guess is the variation is just measurement 'noise', not actual voltage
> variation.
> It only occurs during 100% stress tests, not in any static situation.
> Jack R.



 
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Paul
Guest
Posts: n/a
 
      06-26-2007, 05:48 PM
Michel R. Carleer wrote:
> Well, in my case, I can tell you that the ~0.1V variation has nothing to do
> with noise. It is indeed clearly due to the C2D going into idle power saving
> mode:
> - As long as I do nothing with my PC, the voltage is around 1.14 +/- 0.01 V.
> As soon as I start using the CPU heavily (Orthos or some other intensive
> prog), the voltage raises to 1.22 +/- 0.01 V.
> - It happens completely in sync with the clock multiplier going from x 6 to
> x 9. And back when going back to idle.
> OK, this is all with an Asus P5W DH mobo.
> Speedfan gives me the exact same figures.


There are two major components to voltage variation.

1) Variation due to Speedstep (EIST). OS changes the FID/VID on the fly,
based on processor loading. This can be disabled (a couple different
ways).

2) Load line variation. Popularly referred to as "droop". The amount of
droop is specified in the processor datasheet. There is a min and a
max load line for the processor. Removing all the voltage droop, would
actually violate the processor spec. A certain amount of droop is
normal, and the acceptable range of load lines is documented by Intel.

For example, on my processor, I might expect to see the measured voltage
drop by 0.15V, if the processor goes from no load to full load. That is
perfectly normal and since VID is fixed on my processor (no EIST), the
0.15V change is due to the load line. Each family of processors has
its own load line, so the number for Core2 Duo could be a different one.

You can see min, max, and nominal load lines, on page 21 here, for Core2.
A motherboard is supposed to stay between min and max, when the regulator
is designed for Vcore.

http://download.intel.com/design/pro...s/31327804.pdf

Paul

>
> "Jack R" <(E-Mail Removed)> wrote in message
> news:Xkbgi.11$%(E-Mail Removed)...
>>> "Jack R" <(E-Mail Removed)> wrote in message
>>> news:ZXVfi.32$(E-Mail Removed)...
>>>> What utility/program do you folks use to measure the CPU core voltage?
>>>> I've been trying an assortment and getting varying results, so I don't
>>> know
>>>> what to trust, and which to use as a guide for OC settings.
>>>>
>>>> I get:
>>>>
>>>> CPU-Z 1.40: 1.213V (under stress testing, jumps to 1.440V and back)
>>>> CoreTemp 0.95: 1.3250V
>>>> BIOS: 1.48V
>>>> PCProbeII, SpeedFan and FreshDiag: 1.52V
>>>>
>>>> This is on an ASUS P5N-E SLI mb, with an Intel C2D E6600, set at +.100
>>>> in
>>>> the BIOS.
>>>>
>>>> Thanks for help and suggestions,
>>>>
>>>> Jack R.
>>>>
>>>> (Currently running at 3.3GHZ, mem at 856MHz, video +15% OC)
>>>>
>>>>
>>> "M. R. Carleer" <(E-Mail Removed)> wrote in message
>>> news:f5r6o7$908$(E-Mail Removed)...
>>> The E6600 has a feature by which it saves power when idle. It does this
>>> in
>>> two ways that I know of: lowering the internal clock multiplier (from x9
>>> to
>>> x6) and lowering the requested VCore by about 0.2V.
>>> This explains what you read in CPU-Z, unless you specifically disabled
>>> the
>>> power saving feature in the BIOS.
>>> As for the other progs, I don't use them so cannot comment (except for
>>> speedfan which I use only to measure temps).

>> Thanks for your reply.
>> I have all of the power saving features turned off.
>> My guess is the variation is just measurement 'noise', not actual voltage
>> variation.
>> It only occurs during 100% stress tests, not in any static situation.
>> Jack R.

>
>

 
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Forrest
Guest
Posts: n/a
 
      06-26-2007, 07:53 PM

"Jack R" <(E-Mail Removed)> wrote in message
news:ZXVfi.32$(E-Mail Removed)...
> What utility/program do you folks use to measure the CPU core voltage?
> I've been trying an assortment and getting varying results, so I don't
> know what to trust, and which to use as a guide for OC settings.
>
> I get:
>
> CPU-Z 1.40: 1.213V (under stress testing, jumps to 1.440V and back)
> CoreTemp 0.95: 1.3250V
> BIOS: 1.48V
> PCProbeII, SpeedFan and FreshDiag: 1.52V
>
> This is on an ASUS P5N-E SLI mb, with an Intel C2D E6600, set at +.100 in
> the BIOS.
>
> Thanks for help and suggestions,
>
> Jack R.
>
> (Currently running at 3.3GHZ, mem at 856MHz, video +15% OC)
>
>

Am I reading you correctly? You have all the energy saving mods turned off
and your voltage goes "UP" when you apply a load to the CPU? I thought it
should go down when a load is applied ... my E-6600 always does. I thought
that was the v-droop effect.


 
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Michel R. Carleer
Guest
Posts: n/a
 
      06-26-2007, 11:01 PM
Yeah, going from 1.14 idle to 1.22 under full load seems like a droop to
you?

"Paul" <(E-Mail Removed)> wrote in message news:f5rjgd$i93$(E-Mail Removed)...
> Michel R. Carleer wrote:
>> Well, in my case, I can tell you that the ~0.1V variation has nothing to
>> do with noise. It is indeed clearly due to the C2D going into idle power
>> saving mode:
>> - As long as I do nothing with my PC, the voltage is around 1.14 +/- 0.01
>> V. As soon as I start using the CPU heavily (Orthos or some other
>> intensive prog), the voltage raises to 1.22 +/- 0.01 V.
>> - It happens completely in sync with the clock multiplier going from x 6
>> to x 9. And back when going back to idle.
>> OK, this is all with an Asus P5W DH mobo.
>> Speedfan gives me the exact same figures.

>
> There are two major components to voltage variation.
>
> 1) Variation due to Speedstep (EIST). OS changes the FID/VID on the fly,
> based on processor loading. This can be disabled (a couple different
> ways).
>
> 2) Load line variation. Popularly referred to as "droop". The amount of
> droop is specified in the processor datasheet. There is a min and a
> max load line for the processor. Removing all the voltage droop, would
> actually violate the processor spec. A certain amount of droop is
> normal, and the acceptable range of load lines is documented by Intel.
>
> For example, on my processor, I might expect to see the measured voltage
> drop by 0.15V, if the processor goes from no load to full load. That is
> perfectly normal and since VID is fixed on my processor (no EIST), the
> 0.15V change is due to the load line. Each family of processors has
> its own load line, so the number for Core2 Duo could be a different one.
>
> You can see min, max, and nominal load lines, on page 21 here, for Core2.
> A motherboard is supposed to stay between min and max, when the regulator
> is designed for Vcore.
>
> http://download.intel.com/design/pro...s/31327804.pdf
>
> Paul
>
>>
>> "Jack R" <(E-Mail Removed)> wrote in message
>> news:Xkbgi.11$%(E-Mail Removed)...
>>>> "Jack R" <(E-Mail Removed)> wrote in message
>>>> news:ZXVfi.32$(E-Mail Removed)...
>>>>> What utility/program do you folks use to measure the CPU core voltage?
>>>>> I've been trying an assortment and getting varying results, so I don't
>>>> know
>>>>> what to trust, and which to use as a guide for OC settings.
>>>>>
>>>>> I get:
>>>>>
>>>>> CPU-Z 1.40: 1.213V (under stress testing, jumps to 1.440V and back)
>>>>> CoreTemp 0.95: 1.3250V
>>>>> BIOS: 1.48V
>>>>> PCProbeII, SpeedFan and FreshDiag: 1.52V
>>>>>
>>>>> This is on an ASUS P5N-E SLI mb, with an Intel C2D E6600, set at +.100
>>>>> in
>>>>> the BIOS.
>>>>>
>>>>> Thanks for help and suggestions,
>>>>>
>>>>> Jack R.
>>>>>
>>>>> (Currently running at 3.3GHZ, mem at 856MHz, video +15% OC)
>>>>>
>>>>>
>>>> "M. R. Carleer" <(E-Mail Removed)> wrote in message
>>>> news:f5r6o7$908$(E-Mail Removed)...
>>>> The E6600 has a feature by which it saves power when idle. It does this
>>>> in
>>>> two ways that I know of: lowering the internal clock multiplier (from
>>>> x9 to
>>>> x6) and lowering the requested VCore by about 0.2V.
>>>> This explains what you read in CPU-Z, unless you specifically disabled
>>>> the
>>>> power saving feature in the BIOS.
>>>> As for the other progs, I don't use them so cannot comment (except for
>>>> speedfan which I use only to measure temps).
>>> Thanks for your reply.
>>> I have all of the power saving features turned off.
>>> My guess is the variation is just measurement 'noise', not actual
>>> voltage variation.
>>> It only occurs during 100% stress tests, not in any static situation.
>>> Jack R.

>>


 
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Jack R
Guest
Posts: n/a
 
      06-26-2007, 11:04 PM

"Forrest" <(E-Mail Removed)> wrote in message
news:g9egi.18041$(E-Mail Removed) et...
>
> "Jack R" <(E-Mail Removed)> wrote in message
> news:ZXVfi.32$(E-Mail Removed)...
>> What utility/program do you folks use to measure the CPU core voltage?
>> I've been trying an assortment and getting varying results, so I don't
>> know what to trust, and which to use as a guide for OC settings.
>>
>> I get:
>>
>> CPU-Z 1.40: 1.213V (under stress testing, jumps to 1.440V and back)
>> CoreTemp 0.95: 1.3250V
>> BIOS: 1.48V
>> PCProbeII, SpeedFan and FreshDiag: 1.52V
>>
>> This is on an ASUS P5N-E SLI mb, with an Intel C2D E6600, set at +.100 in
>> the BIOS.
>>
>> Thanks for help and suggestions,
>>
>> Jack R.
>>
>> (Currently running at 3.3GHZ, mem at 856MHz, video +15% OC)
>>
>>

> Am I reading you correctly? You have all the energy saving mods turned off
> and your voltage goes "UP" when you apply a load to the CPU? I thought it
> should go down when a load is applied ... my E-6600 always does. I thought
> that was the v-droop effect.
>

You are reading that correctly, but as I said in another reply, I don't
trust the higher reading to be accurate, although it might be.
Other programs are not showing that variation.
But, I still do not know who to believe. Is it running at 1.2, 1.3, 1.4 or
1.5V?
Thanks,
Jack R.

 
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Forrest
Guest
Posts: n/a
 
      06-27-2007, 12:41 AM

"Michel R. Carleer" <(E-Mail Removed)> wrote in message
news:46819a97$0$13864$(E-Mail Removed)...
> Yeah, going from 1.14 idle to 1.22 under full load seems like a droop to
> you?
>

No it doesn't seem like a droop to me ..... that's exactly my point .....
It's going up under a load instead of the expected decrease in voltage.


 
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Paul
Guest
Posts: n/a
 
      06-27-2007, 01:32 AM
Forrest wrote:
> "Michel R. Carleer" <(E-Mail Removed)> wrote in message
> news:46819a97$0$13864$(E-Mail Removed)...
>> Yeah, going from 1.14 idle to 1.22 under full load seems like a droop to
>> you?
>>

> No it doesn't seem like a droop to me ..... that's exactly my point .....
> It's going up under a load instead of the expected decrease in voltage.
>


Ah, the mysteries of computers :-)

Maybe it is the "AI Overclocking" profile feature ?

One of the reasons I set a lot of stuff on "manual" on my
boards, is to avoid exactly this kind of stuff. BIOS
designers do all sorts of crazy things behind your
back.

Paul

 
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