CPU voltages

[clarkey01]

Hi guys

quick question

I get different readings from my Bios/CPU-Z/Core temps

If I set a voltage in the bios, can I be sure that is the correct voltage and assume CPU-z is just off its tits?

Many thanks guys

 

[Tempered81]

cpu-z is right

 

[Extelleron]

The voltage you set in BIOS cannot be relied upon when the CPU is under load in Windows. Vdroop means that the real voltage is going to be lower (slightly or significantly, depending on mobo/settings) under load, so you need to read the voltage when running Prime95, etc.

Generally CPU-Z is pretty accurate, but the only way to be 100% sure is to actually check the voltage with a multimeter. I've never done this; as long as the voltage seems reasonably (slightly lower than BIOS setting) then it can be trusted.

I had an experience with my AM2 setup where the voltage shown was ~.1V higher than in BIOS.... really don't know which was correct there. I suspect CPU-Z was closer to the truth though.

 

[clarkey01]

CPU-Z Shot

Are my voltages ok? Can I go lower and maintain 2.8 Ghz ?

 

[Tempered81]

Originally posted by: clarkey01
CPU-Z Shot

Are my voltages ok? Can I go lower and maintain 2.8 Ghz ?

are you under load here, what are the temps? You possibly could lower vcore until you have issues passing prime.

 

[clarkey01]

Originally posted by: jaredpace

Originally posted by: clarkey01
CPU-Z Shot

Are my voltages ok? Can I go lower and maintain 2.8 Ghz ?

are you under load here, what are the temps? You possibly could lower vcore until you have issues passing prime.

Thats under prime 95 blend, temps at full load are 55C

 

[Tempered81]

drop it a notch in your BIOS and see if Prime passes. I'll bet the temps will be <55

 

[clarkey01]

Originally posted by: jaredpace
drop it a notch in your BIOS and see if Prime passes. I'll bet the temps will be <55

Hmm I set it to 1.275 in the Bios and I get this at full load

CPU-z

 

[Idontcare]

Originally posted by: Extelleron
I had an experience with my AM2 setup where the voltage shown was ~.1V higher than in BIOS.... really don't know which was correct there. I suspect CPU-Z was closer to the truth though.

There will be a voltage offset between what you set the BIOS voltage to be set to by the mobo versus what the mobo hardware actually delivers to the socket. Sometimes it is high (setting 1.2V in BIOS will deliver 1.25V at the CPU...a +0.05 Voffset) and other times it will be negative.

The difficulty in knowing what your Voffset is for any given mobo is that you only see the "net net" of Voffset and Vdrop at idle. So you know what you set Vcore to in the BIOS, and you see what it is when the chip is at idle but you don't know whether you have a large or small Voffset working for or against a large or small Vdrop on the chip itself.

 

[clarkey01]

Originally posted by: clarkey01

Originally posted by: jaredpace
drop it a notch in your BIOS and see if Prime passes. I'll bet the temps will be <55

Hmm I set it to 1.275 in the Bios and I get this at full load

CPU-z

Is this normal ?

 

[Idontcare]

Originally posted by: clarkey01

Originally posted by: clarkey01

Originally posted by: jaredpace
drop it a notch in your BIOS and see if Prime passes. I'll bet the temps will be <55

Hmm I set it to 1.275 in the Bios and I get this at full load

CPU-z

Is this normal ?

Yes, a 0.1V drop from Vdroop is normal.

See the middle graph in this anandtech report: http://www.anandtech.com/cpuch...howdoc.aspx?i=3184&p=5

 

[clarkey01]

what do you reckon I can get away with ?

Is there a list of OC's I can refer to?

 

[Idontcare]

Originally posted by: clarkey01
what do you reckon I can get away with ?

At 3GHz? Maybe 1.2V idle, 1.1V loaded. Possibly lower but not by much.

Originally posted by: clarkey01
Is there a list of OC's I can refer to?

I'm sure there is such a list somewhere on the web but I'm not aware of any to point you towards.

 

[clarkey01]

Originally posted by: Idontcare

Originally posted by: clarkey01
what do you reckon I can get away with ?

At 3GHz? Maybe 1.2V idle, 1.1V loaded. Possibly lower but not by much.

Originally posted by: clarkey01
Is there a list of OC's I can refer to?

I'm sure there is such a list somewhere on the web but I'm not aware of any to point you towards.

I will try tonight and post my results

 

[geokilla]

I have the vcore in the BIOS set to 1.32V, and this is what I get under F@H load. In PC Probe, it says that I got 1.36V. So which one would be correct here? My temps are in the mid to low 50s.

 

[Tempered81]

Originally posted by: clarkey01

Originally posted by: clarkey01

Originally posted by: jaredpace
drop it a notch in your BIOS and see if Prime passes. I'll bet the temps will be <55

Hmm I set it to 1.275 in the Bios and I get this at full load

CPU-z

Is this normal ?

Yeah

Originally posted by: geokilla
I have the vcore in the BIOS set to 1.32V, and this is what I get under F@H load. In PC Probe, it says that I got 1.36V. So which one would be correct here? My temps are in the mid to low 50s.

.14 vdroop

I'd say cpuz was right @ 1.18v