CPU Voltage Measurements

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)

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" wrote in message
...
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)

"Jack R" wrote in message
...
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" wrote in message
...
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.

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" wrote in message
...

"Jack R" wrote in message
...
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" wrote in message
...
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.

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" wrote in message
...
"Jack R" wrote in message
...
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" wrote in message
...
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.

"Jack R" wrote in message
...
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.

Yeah, going from 1.14 idle to 1.22 under full load seems like a droop to
you?

"Paul" wrote in message ...
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" wrote in message
...
"Jack R" wrote in message
...
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" wrote in message
...
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.

"Forrest" wrote in message
et...

"Jack R" wrote in message
...
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.

"Michel R. Carleer" wrote in message
...
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.

Forrest wrote:
"Michel R. Carleer" wrote in message
...
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