CPU Core Voltage Offset Mode Overclocking

Originally written by Raja from ASUS North America, this guide discusses the principles of the less-used or misunderstood Offset Mode for CPU overclocking or even underclocking (if you’re applying the theory to non-ROG hardware).

For the Maximus IV and Maximus V Series Motherboards

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:

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:

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.