Voltage question

[Riccochet]

When applying voltage to my CPU should I be more concerned over what is set in the bios or what CPU-z is reading? I guess I'm a littel confused over this.

 

[Nenu]

Bios
However, if something is wrong with the mobo, CPU-Z might be highlighting it.
See what it says in the CMOS under the PC health section.
If CPU-Z doesnt agree with the reported voltage in use, its most likely CPU-Z that is reading it wrong.

If still concerned, check the actual voltage with a multimeter, you will need to find the points to measure from.

 

[Riccochet]

Set in bios it's at 1.275, PC health status indicates 1.236. So, I guess I'm giving the proc 1.236v and not 1.275v? That's my question.

 

[Nenu]

Yes, as close as can be reported by the motherboards sensors.
It could be that it really is getting 1.275V and the sensor is inaccurate.

Either way, the difference is small and given the inaccurate nature of sensors and implemented voltages, I wouldnt worry.
Keep an eye on the temps (with the inaccurate sensors lol) and dont exceed what are regarded to be safe voltage settings.

If ever you need full confirmation use a voltmeter and external calibrated temp sensor.

 

[Riccochet]

I taking it I should trust the motherboard sensor readings over the bios settings. Not that my voltages are in danger of damaging anything. 3Ghz on stock voltage is fine with me. I was just curious as to what I should be paying attention to when I take it higher. For instance, at 3.4 I need to give it 1.43v in bios, which is around 1.34v actual. According to PC health anyways. Is that the voltage I should be watching then?

So, like, when I set it to 1.5v in bios, and in PC health it indicates 1.45v or whatever....should I be concerned about the 1.45 or 1.5? This is hypothetical btw.

 

[Nenu]

tbh all readings from a PCs sensors need to be taken with a pinch of salt.
They might be dead on right but they can also be wildy inaccurate.

I wouldnt worry about them too much unless you find that the readings are so bad it affects what you need to do.
Use the readings as a guide to any changes that are ocurring, like temps rising or voltage fluctuating a lot.
You cant trust the absolute values.
Chances are they are going to be within 10% of the real figures but there is NO guarantee.

There is no way to know the exact voltage applied to your CPU unless you measure it with a calibrated meter.
Most decent meters you can buy these days are within a couple of % accurate or better.

Also worthy of note:
Once you have set a voltage in the BIOS, the voltage to your CPU will not remain constant.
The more load applied to your CPU, the more power it will require and thus more current will flow
Due to resistance in the power circuitry, the more current that flows, the more voltage will drop across these circuits, thus reducing the actual voltage fed to your CPU.
Its the same for everyone.

Some motherboards have compensatory circuits to keep the voltage more stable but there will be a variance no matter what.
Its nothing to worry about unless the constantly changing variations get really big and affect your stability.

 

[Riccochet]

tbh all readings from a PCs sensors need to be taken with a pinch of salt.
They might be dead on right but they can also be wildy inaccurate.

I wouldnt worry about them too much unless you find that the readings are so bad it affects what you need to do.
Use the readings as a guide to any changes that are ocurring, like temps rising or voltage fluctuating a lot.
You cant trust the absolute values.
Chances are they are going to be within 10% of the real figures but there is NO guarantee.

There is no way to know the exact voltage applied to your CPU unless you measure it with a calibrated meter.
Most decent meters you can buy these days are within a couple of % accurate or better.

Also worthy of note:
Once you have set a voltage in the BIOS, the voltage to your CPU will not remain constant.
The more load applied to your CPU, the more power it will require and thus more current will flow
Due to resistance in the power circuitry, the more current that flows, the more voltage will drop across these circuits, thus reducing the actual voltage fed to your CPU.
Its the same for everyone.

Some motherboards have compensatory circuits to keep the voltage more stable but there will be a variance no matter what.
Its nothing to worry about unless the constantly changing variations get really big and affect your stability.

Well, 0.05 to 0.1 volts could affect what I'm trying to accomplish. So, yes, it does matter. You just added another layer to the conondrum. Are you implying I need to meter the voltage going to my cpu?

FWIW CPU-z and PC Health both report nearly the same voltage as opposed to what's set in the bios, which is higher.

 

[Nenu]

You only need to use a meter if there is valid reason for concern (or you want to know the real voltage)
ie if the reported voltage is high enough to damage the CPU or if the temps are outside safe operating range.

btw I havent added any complexity, this is just the way it is.
Most of the time you can ignore it and just use the reported values.
They dont actually matter if your PC is stable and nothing is being overdriven.

If you need another 0.05V and your temps are good, theres no need to worry unless you are running the new E8x00 45nM CPU's.