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Overclocking Using Offset Mode for CPU Core Voltage

Raja
Level 13
Many of you have asked us how to use Offset Mode in BIOS to over or underclock a CPU, so we’ve put together a quick guide that should help users better understand how to use
the Offset Mode function.

We’ve tried to keep things as simple as possible, while providing enough information to help further understanding of this feature.

Intel programs each processor with a stock voltage using a binary code (known as VID). This binary code is utilized by the motherboard voltage regulator module to set the correct
voltage for the processor at stock operating frequency.

At stock, Intel’s power saving features such and SpeedStep, EIST and C-States are active. Under light loading conditions, SpeedStep reduces the CPU multiplier thus lowering the
operating frequency. EIST dynamically lowers the VID while various C-States sends parts of the processor into low power or off state to help save power consumption.

As we increase the processor’s operating frequency, we’re going to need to increase VCore in order to facilitate higher switching frequencies of the processor core.
The conventional method of doing this is simply to set voltage control to manual mode and type in the required voltage for stability at the selected operating frequency.
However, the side effect of using this method is that the applied voltage code (VID) remains static under all loading conditions so we end up increasing power consumption
and heat production under light loading conditions unnecessarily.

The workaround for this is to use Offset Mode in BIOS to set the processor’s operating voltage. In order to do this on the ROG boards we need to set CPU Voltage from
Manual Mode to Offset Mode:







Note that on the ROG boards; Phase Control needs to be set changed from Extreme to Standard, Optimized or Manual in order for Offset Mode to become available in the CPU Voltage menu.




We recommend that you set Load-line Calibration to 75% if using Offset Mode to control Vcore.





With these two functions set, we can move back to the previous screen and change the CPU Turbo multiplier to a higher value, so that the processor ramps
to a higher frequency when under sufficient load from software:



BIOS displays the target CPU frequency on the same page.



As pointed out in earlier guides, most CPUs will scale to 4.5GHz with the right cooling. We’d recommend you start out lower than that to get a feel for
how well your processor scales with voltage. In our example we’ve selected a 43X multiplier, giving us a Turbo frequency circa 4.3GHz under load.

At this point we can reboot the system; the CPU voltage will be offset from stock voltage automatically – as you increase operating freqeuncy, the default voltage
will automatically increase. In order to find out what the new load voltage is, we can boot Windows and run a stress test, while keeping ROG CPU-Z open to get a rough
idea of how much voltage the processor is seeing under load or if you’re handy with a multimeter, the ROG boards have a measurement point situated near the DIMM
slots allowing for a more accurate reading.





AUTO default voltages for idle and full load conditions. These will vary from processor to processor.




BIOS may have applied more voltage than the CPU requires for stability at 4.3GHz, in which case we simply enter BIOS and use the
Offset Mode function to decrease VID appropriately:








With the “-“, (negative) voltage range selected, the voltage you select will be subtracted from the load voltage we saw in the operating system.
For example if our full load voltage was 1.376V in the operating system, and we’d like it to be 1.32V instead, we simply set 0.05V as
the negative offset (1.37V-0.05V=1.32V).








Bear in mind though that this will also offset your idle voltage by the same value. As an example, with the default voltage settings,
our 2500K processor’s idle voltage (at 16x CPU multiplier ratio) is 1.045V. If we subtract 0.05V from the full load voltage, the idle voltage
will be reduced by the same value:








So if we offset the voltage too far with the negative voltage scale, there will come a point where the idle voltage is no longer sufficient to sustain
the idle processor clock frequency.

If we wish to add voltage to the full load VID, we simply use the + offset and increase to increase the voltage level. 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.








Similarly the idle voltage is increased by only 0.025V, too:







That’s why we recommend getting a feel for how the offset range works with your processor, before pushing the system hard. Offset Mode may appear
to be an overly complex way to overclock initially, but once you get the hang of it the results are very worthwhile.
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xeromist
Moderator
This is really cool. I never knew this was available. We had someone asking a question like this just the other day here on the forums.
A bus station is where a bus stops. A train station is where a train stops. On my desk, I have a work station…

Fr0stX
Level 7
Is this feature available on the Rampage III Extreme? I ws the guy who asked the question and I fear that the aswer will be "on every board except the Rampage III extreme"...
I7-10700K @5.0Ghz
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Corsair HX850i

ottoyu34
Level 9
Awesome guide, it should be all clear now

Thank you this is VERY helpful! I've gone through so many combinations of settings and BIOS over the last couple of months looking for a stable (yet cool and efficient) 4.8-4.9 OC. I should have kept notes of what I have done so far. But I've tried several auto tunes using some default settings and then some manual and enabled settings and usually come across consistent mid to high 30 degree idle temps with about 120W of power consumption. Yesterday using 1303 I manually OC'ed to 4.9 using the guide on the third post of this thread. http://www.asusrog.com/forums/showthread.php?2157-Maximus-IV-Extreme-Bios-Sandybridge-CPU-Overview-a...

It's a great set up except it runs about 50 degrees at idle and uses about 165W of power. Not that it's a problem but I'd always like to try and get it so when at idle it stays efficient. I would have to assume once you get into the 4.8+ range the Vcore can't dip down too low because the BCLK and CPU ratio are too high and would cause it to lockup at idle (in essence the system would actually run better when it's being used). Which is probably why this thread mentions the offsetting is good to 4.5. I would also have to assume if I use some offsetting it might drop the temps and power consumption down some, but won't get into the 30's at 120W like with a 4.6 set up. I guess the only way to find out is to try. Anybody feel free to share their results if you've tried this. I try to add mine in case others are looking for the same ideas. I I think first I might try 1407 and 1409 with the exact same settings I'm using now to see if there is any difference and then try offsetting based on which BIOS works best. Thanks!

Praz
Level 13
Offset voltage will work at higher overclocks. Depending on the system it may take some time finding the optimal settings though. Once you are stable under load at these higher clocks at-idle instability can become an issue. If that is the case there are a couple of different approaches that can be used. A slight increase of the offset voltage above what is needed for loaded stability may boost idle voltage enough to bring about stability at that end also. If not you can lower LLC one notch which will require a considerable increase of offset voltage to get back to your original loaded voltage value. This should also raise idle voltage to an acceptable level to maintain stability at idle. This will allow you to stay with your desired overclock while dropping to 1600MHz at around 1.00V - 1.10V at idle.

JJFIVEOH
Level 7
I have since flashed to 1409 and put all my settings exactly the way they were with 1303 when idle temps were at 50 and power usage was 160W. Now they are back to mid to high 30's @ 120W just like they are at OEM default. Of course it's using 1.42V 100% of the time, for some reason the power usage increased with 1303. I was more concerned about the heat and efficiency but since it is now back to where it was previously, is there any reason besides CPU wear that I should consider messing with offsetting?

I ran a complete 3DMark test at max settings with 1920 x 1080 res and came through with flying colors. I understand 3DMark is for graphics, but it does put the CPU through a good workout.

Praz, thank you for all your help BTW.

Quick question..... when it says this:


Note that on the ROG boards; Phase Control needs to be set changed from Extreme to Standard, Optimized or Manual in order for Offset Mode to become available in the CPU Voltage menu.

Which of the three is best for shooting for 4.8-5.0? Or does it not matter?

JJFIVEOH wrote:
Quick question..... when it says this:



Which of the three is best for shooting for 4.8-5.0? Or does it not matter?

These setting should be good to 5.0GHZ - 5.1GHz.


Praz wrote:
These setting should be good to 5.0GHZ - 5.1GHz.



Raja@ASUS wrote:
Optimized or Manual should do it - I can't quite remember the options off the top of my head in the Manual sub-section, but one of the more aggressive options in there should suffice.

-Raja


Thanks guys. I stuck with the optimized and as I mentioned already it is very stable at 1.38V now @ 4.8. I chose manual voltage instead of offset because I felt there is way too much range between min and max in the offset. Without offsetting anything +/- it did dip down to 1.1x range at idle but it did spike well into the 1.5x range (even saw a 1.61 once) which doesn't sit well with me. I wish there was a way to control the range as well. When I set a - offset I think it was too low because a couple of times I had problems booting.

Seeing is I have run several benchmark programs to check stability with 4.8 @ 1.38 and have yet to have a single problem, I don't see any benefit in the offset going above 1.4 much less close to 1.6. I can see this being beneficial for a lower OC though.

As for the 5.1 setup, thank you! That works just as well but I needed to jump to 1.45V for this to work. I am satisfied now knowing I can hit 5.1 and gotten more familiar with all the settings which is what I wanted in the first place. 4.8 is perfect for everyday multi-tasking over the stock 3.4.

One thing I have noticed is with my current setup at 4.8 I am using 112-117 watts at idle whereas I was using in the 120 range with all defaults. That's not what surprises me, what does surprise me is the default 4.6 OC uses 160 watts at idle yet an extreme auto tune that hits 4.6 only uses 120-130. Not sure which settings are changed from default to auto tune that would make auto tune run more efficient. Just something I noted in case anybody else is reading this. :cool: