CPU Core Volts - Trust Bios or Windows apps?

CaNNoN_1981 · 13 Feb 2009 at 22:44

Hi

According to cpuz and everest my cpu core is running at 1.41v

In bios I've had to set the core to 1.44375 to get that reading in windows

Current overclock is in sig.

If I set the cpu mhz to 435 I dont post, I've had 3.5ghz out of this cpu on a diff mobo although I cant remember what I had the volts set too.

I believe anything over 1.45 and your pushing your luck.

At the current oc the cpu idles at 28º and pushes 40º while full load.

I dont wonna pop the cpu by pushing too many volts through it.

Do I trust the 1.41 in windows or the 1.44375 in bios???

Ta

RJC · 13 Feb 2009 at 22:50

The voltage drop they call vdroop - I think someome will correct me if I am wrong.

Big.Wayne · 13 Feb 2009 at 23:53

CaNNoN_1981 said:
Do I trust the 1.41 in windows or the 1.44375 in bios???

Hey CaNNoN,

do you mean the voltage you set in BIOS or the Voltage that is displayed in the BIOS Health-Menu?

The vCore you manually set in the BIOS is a rough approximation and you nearly always end up with less. The result you see in the CPU-z Core-Voltage display should normally be the same as the BIOS Health-Menu display and I believe is accurate.

The difference between the voltage you set and the actual voltage you get is known as vDrop and is pretty normal, you just calibrate for the vDrop by adjusting the voltage up a few notches until you get the figure you (or your chip) requires.

The other vCore fluctuation you may run across is when the voltage sinks lower when the processor is under heavy load, this sagging is referred to as vDrOOp and is pretty much an undesirable effect as to compensate for vDroop you again have to bump up the vCore in BIOS. Having said that most modern motherboards when paired with a decent PSU will largely remove the effects of vDroop and you will find that the voltage runs like a flatline (no rise, no droop) . . . if your running your machine with EIST(Speedstep) disabled then this voltage flatline makes perfect sense as any fluctuation to the vCore while its running at full speed will produce a failure of some sort.

So thats your basic vDrop and vDroop explanation . . . there is however a third variation of voltage fluctuation and I'm not sure whats its official name is so I will call it vRise or reverse-vDrOOp!

vRise is the exact opposite of vDrOOp and is a scenario where while the processor is idle (inc Speedstep) it receives less voltage but once the beast is unleashed the voltage rises to the amount you wanted! Kinda makes sense if you think about it!

In the screenie below you can see the effects of vRise although its very slight and I would be happier if the vCore sank a lot lower when the chip was idle but at least its a step in the right direction!

1.34375 vCore BIOS-Set

CaNNoN_1981 · 14 Feb 2009 at 00:23

Big.Wayne said:
do you mean the voltage you set in BIOS or the Voltage that is displayed in the BIOS Health-Menu?

Just had a quick look in bios, the voltage set is 1.44375 but in the bios health menu its actually reporting 1.41 pretty much similar to cpuz and everest in windows etc

The volts in windows dont really change much, stays at 1.41 99% of the time and drops to 1.392 1% of the time.

Big.Wayne · 14 Feb 2009 at 00:54

CaNNoN_1981 said:
the voltage set is 1.44375 but in the bios health menu its actually reporting 1.41 pretty much similar to cpuz and everest in windows etc

The vCore figure that is important is the figure you read in the BIOS Health-Menu and CPU-z.

If you give your technical settings to another user you should mainly quote the resulting figure . . . . if you want to be more precise then you would quote the idle/load vCore and last of all is the figure you [set] in the BIOS.