View Full Version : ? regarding loadline gigabyte p35 dq6

02-19-2008, 06:33 AM
As I understand it (correct me if I'm wrong), with loadline disabled, suppose I choose 1.25v bios as cpu vcore. That will actually set vcore at 1.23 volts idle (Voffset). During load with dual core that may decrease to 1.22 (Vdroop), but immediately after load stops, before the vrm circuit can decrease the voltage in time for new decreased workload there is overshoot to 1.25v as a spike before decreasing back to 1.23 idle. Thus when you are choosing 1.25 volts in bios, you are choosing max volts ie, overshoot max, and not idle volts.

My guess how loadline works, again, correct me if I am wrong. When loadline is enabled, and you choose 1.25 volts in bios, you are then choosing the idle volts and thus it idles at 1.25V. During load you still see vdroop to 1.24v, and overshoots to 1.27v.

In other words having loadline disabled and a vcore of 1.25v bios (which sets idle at 1.23v measured) is the exact same thing as having loadline enabled and setting vcore to 1.23v bios (idle at 1.23v measured).

Is that correct? Or does it work in some other way. If so, I actually like loadline as it simply gives me the option of using bios to set volts at either max spike or more what I prefer, idle volts.

Either way, can you explain anandtech's statement... "As we have discussed before Loadline Calibration is best left disabled, especially when using the newer 45nm CPUs. Our testing has shown these settings induce power instabilities, even when using lower voltages. In addition, when enabled the option sometimes requires more CPU voltage than would otherwise be necessary, meaning increased power dissipation and higher temperatures."

Bottom line if loadline on the gigabyte board is just a simple 4 notch .02v sensor calibration, then I can ignore anandtechs statement, but if loadline calibration is doing something else, than the "power instabilities" might lead me to stay away from it.

thanks in advance for any replies...

02-19-2008, 10:28 AM
I enable mine on DS4 and load or idle volts remain a constant. PERIOD

With it on Auto it does fluctuate a .1v or similar as what you said, but never has drop larger then .1

With it disabled...sometimes I see .2 or more depending on the voltage set

So all in all it really depends on what you are trying to accomplish as to what you would want to set it on, in my opinion

02-19-2008, 05:34 PM
bios changes volts in steps of .00625v, sensor as read by cpuz, etc changes in steps of .016v, which means at many settings you would not see the sensor change, even though some vdroop exists. So you have no clue what vdroop is unless you are using a $150+ multimeter to measure vcore directly from the board. Using a multimeter, others have measured vdroop to be same with loadline on or off, approximately .01. Not to mention vdroop is simply a protective mechanism to lessen overshoot once load suddenly stops and thus lessen damage from electromigration from higher volts.

But what I am asking is...whether loadline is a sensor calibration change or something else, and if so what?

02-20-2008, 12:27 AM
CPU-z and Everest do see the changes when there is one, I used to mostly use a GA-965P-S3 which had a HUGE Vdroop.

But yeah I do know what you mean, But I am just happy the DS4 has no next to nothing for Vdroop, I was just trying to say the above for a very close guesstimate/example. I knwo there is some Vdroop. Just none in Large amounts like other GA boards

Now if I can see a obvious Vdroop at certain voltages with it off and at that some voltage with it on see nothing, then it is definitely not the same. And I say that meaning at certain voltages across the range the Vdroop is different with either setting.

As for your question, I dunno for sure but if you have the time and patience you may find more info in this thread (Get your brain ready :cantfocus )


02-20-2008, 04:24 AM
yeah, I think your right, it actually does at least reduce vdroop ...to a point below what a .016 stepped sensor can pick up and eliminates Vdrop/offset.

loadline enabled.
bios...........cpuz idle......cpuz load

loadline disabled.
bios...........cpuz idle......cpuz load

But still want to know what it does specifically...though may not find out. Thanks for help.

02-20-2008, 11:30 AM
And where I noticed the variance get smaller was in the 1.4's