http://rog.asus.com/244672013/labels/featured/introduction-to-fully-integrated-voltage-regulators-fivr-on-maximus-vi/ schrieb:
The Key Lesson: VCCIN = +0.4 VCore
Intel defines the VCCIN specification (called the ‘Eventual CPU input voltage’ in the ROG BIOS) in relation to CPU Vcore as follows:
Less than 0.4V – not recommended. Instability is almost guaranteed
0.4V – ideal value
0.4-0.6V – general ‘OK’ range
Above 0.6V – not recommend as long-term damage can occur
Generally speaking, higher VCCIN can cause a higher CPU temperature
As all 5 internal power rails are pulled from the single VCCIN, below 0.4V difference is not recommended as high loading on the;input voltage will cause a voltage drop that can lead to it being lower than the internal voltages. This will cause the system to lock-up. Above the safe range can cause long-term damage due to a larger than necessary potential difference. This is the same reasoning why DDR3 voltage should not exceed 1.5V, as the CPU Uncore can be damaged.
Due to the small voltage difference, the Maximus VI Extreme now has 8 Steps of VCCIN Load-Line Calibration, up from 5 in the previous generation, to more accurately moderate its VCCIN according to detected loading.