I guess I just dont understand offset voltage. Can someone help out here?

[The Sauce]

Just started overclocking my P8Z68-V/Gen3 and 2500k.

The concept of offset voltage seems very simple. You take your base voltage (which seems fixed at 1.200) and add your offset voltage to get your maximum CPU-stressed voltage...correct?

So, 1.200 + 0.04 should give you a maximum voltage under stress of 1.24, right?

However, I see numerous threads here with offset voltage set to say 0.04 and people reporting voltages of 1.38 or ranges, such as 1.35-1.38. I personally tried 0.1 and in CPU-Z saw voltages of close to 1.4. So now I have no idea what this does or how to regulate my voltages in offset mode. Can anyone help me out here?

 

[Puppies04]

As I understand it your basic premise is correct but you fail to take Load line calibration (LLC) into consideration. Do you have it set on? That can also raise voltages to stop BSOD at high levels of load.

 

[Idontcare]

You have to understand first of all the your 2500K has a look-up table encoded internally in which the chip's VID when operating at full load is dependent on the multiplier.

At 3.2GHz (32x multi) the VID reported by the CPU to the BIOS will be something like 1.200V. If you set the offset to 0.04V then the BIOS will attempt to set its VRM's to supply the CPU with VID+offset = 1.2+0.04 = 1.24V

However, if you then overclock the CPU to say 4GHz (40x multi) then the CPU itself will tell the BIOS that its VID is now 1.3V (or thereabouts) and so the BIOS take your offest (0.04V) and adds the currently reported VID to that (1.3+0.04) and sets the mobo's VRM's to supply 1.34V.

If you get anywhere close to 5GHz then you will see the CPU telling the BIOS that the VID is 1.5V (and even higher).

So you need to take into account the dynamic nature of the VID itself when adjusting your Voffset.

 

[The Sauce]

I guess that makes sense. But, then in order to overclock to high levels you can not use Offset mode unless you are willing to subject your CPU to ridiculously high voltages? Right now I am running at 4.8 GHz @ 1.35v. Based on what you say if I used offset mode I would be up close to 1.5v which is probably not realistic for long term use. Is that right?

That would contradict what I read in several places where people were saying that you should use offset mode for higher overclocks to keep your voltages low. Still somewhat confused. If getting up to 5 GHz mandated a ViD of 1.5 using offset mode then how does offset mode help you to get better overclocks and keep your voltages lower than with manual mode?

 

[The Sauce]

Ok, got this off the ASUS site, which seems to shed some light on the subject:

"The “+” offset scale isn’t as direct as the” –“ scale when it comes to changing voltage, that’s because one of the features of SVID (serial VID) is that it allows the processor to request voltage based upon operating frequency, current draw and thermal conditions- hence adding 0.05V to 1.376V results in a full load voltage of 1.40V."

 

[Puppies04]

I guess that makes sense. But, then in order to overclock to high levels you can not use Offset mode unless you are willing to subject your CPU to ridiculously high voltages? Right now I am running at 4.8 GHz @ 1.35v. Based on what you say if I used offset mode I would be up close to 1.5v which is probably not realistic for long term use. Is that right?

If you did find yourself in that hyperthetical situation and you felt that the CPU was demanding more voltage than it actually needed to run stable at that clockspeed you would simply dial in negative offset, it works both ways.

 

[Idontcare]

I guess that makes sense. But, then in order to overclock to high levels you can not use Offset mode unless you are willing to subject your CPU to ridiculously high voltages? Right now I am running at 4.8 GHz @ 1.35v. Based on what you say if I used offset mode I would be up close to 1.5v which is probably not realistic for long term use. Is that right?

That would contradict what I read in several places where people were saying that you should use offset mode for higher overclocks to keep your voltages low. Still somewhat confused. If getting up to 5 GHz mandated a ViD of 1.5 using offset mode then how does offset mode help you to get better overclocks and keep your voltages lower than with manual mode?

I don't see the contradiction. You just use a negative offset instead of a positive one.

If you did find yourself in that hyperthetical situation and you felt that the CPU was demanding more voltage than it actually needed to run stable at that clockspeed you would simply dial in negative offset, it works both ways.

^ this.

 

[The Sauce]

Ok, got it. Didn't understand the "-" offset bit. It's still quite tricky figuring out exactly what voltage you will get with a "+" offset but I guess that will just take some trial and error. Makes things a bit more interesting.

So, it sounds like a good way to approach things would be to overclock to max with manual voltage, then try to find the equivalent offset settings.

 

[abeeftec]

I have a question about this because I have never used Offsets. They just dont seem to make sense. If there is something I am missing I sure would like to know.
I have been doing a massive amount of overclocking in the past 2 years and this is an area I just never touched And not having posted in forums a whole lot I never saw anything on this...

In regards to the 2000K series CPUs...

What is the point of using the offsets? If you are using a negative offset then it seems all you are really doing is setting the voltage to run exactly the same voltage it needs just in a different fashion.

Say I need 1.45 volts to be stable at 5.0ghz.

What would the benifit be of setting the voltage to 1.5v and then offsetting it back down to 1.45?

I would see a possible benifit if I needed 1.45v to be stable at 5.0ghz and I could use an offset in the negative to get my voltage down.


EX. Set voltage 1.45 and a - Offset..

Is the benifit only seen when using speed stepping while overclocking? Is the point so you are not ALWAYS running at that high voltage unless it needs it?


Just to run some benchmarks yesterday, I set my Multiplier at x45 and my voltage on my 2600k to 1.41v and on CPUz it was reading 1.44v with NO OFFSETS and with FULL LLC.(Level 10) Of course that 1.44 was stock and under load it went to 1.48 on CPUz. Yeah I know Horrible chip! Got it from Intel INDS!
^^Maybe if someone sheds some light on what offsets would do for that senario maybe It will make some better sense in a real world application.

 

[Idontcare]

I have a question about this because I have never used Offsets. They just dont seem to make sense. If there is something I am missing I sure would like to know.
I have been doing a massive amount of overclocking in the past 2 years and this is an area I just never touched And not having posted in forums a whole lot I never saw anything on this...

In regards to the 2000K series CPUs...

What is the point of using the offsets? If you are using a negative offset then it seems all you are really doing is setting the voltage to run exactly the same voltage it needs just in a different fashion.

Say I need 1.45 volts to be stable at 5.0ghz.

What would the benifit be of setting the voltage to 1.5v and then offsetting it back down to 1.45?

I would see a possible benifit if I needed 1.45v to be stable at 5.0ghz and I could use an offset in the negative to get my voltage down.


EX. Set voltage 1.45 and a - Offset..

Is the benifit only seen when using speed stepping while overclocking? Is the point so you are not ALWAYS running at that high voltage unless it needs it?


Just to run some benchmarks yesterday, I set my Multiplier at x45 and my voltage on my 2600k to 1.41v and on CPUz it was reading 1.44v with NO OFFSETS and with FULL LLC.(Level 10) Of course that 1.44 was stock and under load it went to 1.48 on CPUz. Yeah I know Horrible chip! Got it from Intel INDS!
^^Maybe if someone sheds some light on what offsets would do for that senario maybe It will make some better sense in a real world application.

The benefit of using an offset voltage adjustment versus manually specifying the voltage is only really relevant when the CPU is idle.

If you manually specify the voltage then your BIOS is going to direct the VRM's to supply that Vcc to the CPU regardless the power-states the CPU is in.

If you specify 1.41V then the CPU is going to get 1.41V regardless whether it is at full load or at idle. (more or less, unless you get your LLC really out of whack and start under/over-volting even further because of the LLC settings)

If you specify a voltage offset then the offset remains fixed (say 0.15V) while the underlying "base" voltage is allowed to change per the CPU's reported VID. So if your chip goes idle and tells the BIOS to supply it with 1.050V then the BIOS will feed it 1.2V (1.050+0.15), but if your chip gets loaded and requests 1.25V the BIOS will feed it 1.40V (1.25+0.15).

The difference is what the CPU sees when idle. And this becomes a problem if you are using negative offsets because then the idle voltage can be too low, even for an idling cpu, and you'll get random BSODs.

 

[abeeftec]

The benefit of using an offset voltage adjustment versus manually specifying the voltage is only really relevant when the CPU is idle.

If you manually specify the voltage then your BIOS is going to direct the VRM's to supply that Vcc to the CPU regardless the power-states the CPU is in.

If you specify 1.41V then the CPU is going to get 1.41V regardless whether it is at full load or at idle. (more or less, unless you get your LLC really out of whack and start under/over-volting even further because of the LLC settings)

If you specify a voltage offset then the offset remains fixed (say 0.15V) while the underlying "base" voltage is allowed to change per the CPU's reported VID. So if your chip goes idle and tells the BIOS to supply it with 1.050V then the BIOS will feed it 1.2V (1.050+0.15), but if your chip gets loaded and requests 1.25V the BIOS will feed it 1.40V (1.25+0.15).

The difference is what the CPU sees when idle. And this becomes a problem if you are using negative offsets because then the idle voltage can be too low, even for an idling cpu, and you'll get random BSODs.

It is correct to say then that the CPU at 4.5ghz will still require higher voltages when Idle while overclocked then at stock speed (Obviously).

So basically it is safe to assume the purpose of using the offset is so that you can get your CPU stable while overclocked at both the lowest IDLE Voltage as well as stable at the lowest LOAD Voltage? Is this the point of Offset?

 

[Kenmitch]

It is correct to say then that the CPU at 4.5ghz will still require higher voltages when Idle while overclocked then at stock speed (Obviously).

So basically it is safe to assume the purpose of using the offset is so that you can get your CPU stable while overclocked at both the lowest IDLE Voltage as well as stable at the lowest LOAD Voltage? Is this the point of Offset?

Yes and no on the idle. Guess it depends on if your doing +/- with the offset depending on the overclock and if you got a good chip.

When using offset voltage sometimes you'll be 100% stable at loads but can get randome bsods at idle or doing low load things like surfing the web. If this happens to you just up the offset a tic or two. If possible try to overclock without load line calibration as it seems to work best at lower overclocks < 4.5ghz and under....At least on my motherboard anyways it allows me to stabalize with lower loaded vcore.

 

[The Sauce]

From what I have read, and also personally experienced, you can get rid of the BSODs at idle by disabling C3/C6. Worked great for me.