NOTE: Modifying voltage settings may damage your processor, negatively affect system stability and can potentially void your processor warranty. Please proceed with caution !
Integrated voltage regulator was introduced in 4th Generation Intel® Core™ processors (code name Haswell). Voltage regulator supplies variable voltage to individual domains within the processor based on their current operating conditions (frequencies, power consumption, heat etc). Integrated voltage regulator is used by the processor to optimize for both performance and energy consumption by dynamically adjusting power delivery to various processor components (core, cache, graphics and system agent).
Depending on the processor model and feature availability you can select a specific domain to make an adjustment of VR settings
Domain list for processors with code-name Haswell and Broadwell:
Domain list for processors with code-name Skylake and later versions:
Graphics Slice (GT Slice)
Graphics Unslice (GT Unslice / iGPU Unslice)
Depending on your CPU model and feature availability each domain is controlling several adjustable settings (planes).
Voltage Mode: Static voltage mode vs Adaptive voltage mode
Voltage: VCore voltage adjustment on the voltage rail. Measured in mV where 1mV = 0.001V.
Voltage Offset: Positive or negative voltage slice that will be applied to an existing (preconfigured) voltage value. Measured in mV where 1mV = 0.001V.
IccMax: Specifies the maximum amount of current that CPU chip is allowed to pull through the voltage rail. Measured in A (amperes)
Ratio: Specifies ratio limit for the component (if ratio setting is enabled and value is set to 0 this can indicate that selected domain is using default value for this setting)
Modifying domain voltage settings
NOTE: While undervolting the CPU is a relatively safe procedure (you can get a BSOD or system freeze if you undervolt below CPU operational limits), overvolting can cause significant damage to your processor.
Based on the information that even CPU chips within the same family, model and stepping can differ from one another due to differences in silicon quality, each CPU comes with factory predefined operational voltage safety margin. This margin helps the processor to maintain predictable and consistent (according to CPU specifications) operation levels across the different chips and scenarios.
What you are trying to do with CPU undervolting is to find a negative voltage offset that will be applied to a preconfigured voltage value for a specific domain and reduce operational voltage without affecting overall system stability
As it was mentioned above this value might not be the same even for the same CPU models. If the voltage reduction is too great you might experience BSOD or a system freeze which will clearly indicate that your CPU needs a higher voltage to operate. The idea here is to experiment with the negative offset and find a value at which your CPU is stable at idle and/or load (depending on your personal goals).
There are few different ways to overvolt your CPU:
By increasing voltage offset which will be applied dynamically when needed
By modifying Vcore voltage to make a constant change in power delivery
Increasing voltage offset has the advantage that your CPU won’t be continuously running with elevated voltage which can have a negative impact on power consumption and thermal output (heat). On the other side by applying the constant amount you will know the exact value by which it was increased.
By increasing the amount of current that your CPU can pull through the voltage rail you can potentially avoid current throttling.