Rampage IV Extreme UEFI Guide for Overclocking

[Raja@ASUS]

Digi+ Power Control



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VCore Load-Line Calibration: Sets a margin between idle and full processor load voltage to compensate for overshoot. To clarify; overshoot is a short duration voltage excursion beyond applied processor VID. We recommend a setting of Medium for most overclocking.

CPU Current Capability: Increases the power threshold before over-current protection limits power (either by shut-off or throttling). A setting of 180% is ample for all types of overclocking.

CPU Voltage Frequency: Sets the switching frequency of the power FETs supplying processor Vcore. Lower switching frequencies lead to a higher VRM efficiency (small power saving) and lower VRM operating temperatures. Setting a higher switching frequency aids transient response (the recovery of voltage to the applied level after a load condition) – at the expense of heat.

VRM Over-temperature Protection: Monitors CPU VRM MOSFET temperatures and if the temperature breaches a certain threshold either throttles the processor clock frequency to reduce current consumption or shuts-down the motherboard to prevent VRM failure. May be turned off is using sub-zero cooling on the processor. For all other purposes, leave this setting enabled and provide active cooling over the CPU VRM heatsink to keep temperatures in-check.

CPU Power Duty Control: Sets the conditions for load balancing across phases. “T.Probe” monitors phase thermal conditions and balances load accordingly. “Extreme” balances the current load across all FETs irrespective of thermal conditions.

VCore MOS volt. Control: Sets the CPU VRM driver output voltage. This setting can be left on Auto for all overclocking. If wishing to experiment with manual settings then bear in mind that most FETs used on motherboards are generally optimised for a VGS of 5V, so a setting of 7V is generally optimal and should provide the best voltage swing.

CPU Power Phase Control: Sets the load dependant phase switching conditions; the VRM is made up of multiple phases (each phase has at least two FETs). During light-load conditions FETs can be switched off to save power. “Standard” and “Optimized” are adequate for most loading conditions and required if you wish to use Offset Mode for Vcore. If pushing processors past 4.8GHz, then Extreme or “Manual” with “Ultra-Fast” is recommended.

CPU Spread Spectrum: Modulates the CPU VRM clock signal to reduce the peak magnitude of radiated noise emission levels (may be of use during audio recording/playback from the analogue audio outputs) . This setting should be used at stock system operating parameters only.

CPU Vcore Boot Up Voltage: Can be left at Auto for normal use. If benchmarking, then setting a lower or higher boot-up voltage for the CPU can aid in ensuring the system POSTs – experiment if experiencing non-POST situations only.

VCCSA Load-Line Calibration: Sets a margin between idle and full System Agent load voltage to compensate for overshoot. We recommend a setting of Medium for most overclocking.

VCCSA Current Capability: Increases the power threshold before over-current protection limits power. Increase to 140% if running 64GB of memory or if running memory speeds in excess of DDR3-2133.

VCCSA Fixed Frequency: Sets the switching frequency of the power FETs supplying the processor System Agent. Lower switching frequencies lead to a higher VRM efficiency (small power saving) and lower VRM operating temperatures. Setting a higher switching frequency aids transient response (the recovery of voltage to the applied level after a load condition) – at the expense of heat.

CPU VCCSA Boot Up Voltage: Can be left at Auto for normal use. If benchmarking, then setting a lower or higher boot-up voltage for the CPU can aid in ensuring the system POSTs at higher DRAM operat8ing frequencies – experiment if experiencing non-POST situations only.




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CPU VTT Switching Freq: Sets the switching frequency of the power FETs supplying VTT. Lower switching frequencies lead to a higher VRM efficiency (small power saving) and lower VRM operating temperatures. Setting a higher switching frequency aids transient response (the recovery of voltage to the applied level after a load condition) – at the expense of heat.


CPU VTT Over-Current Protection: Increases the power threshold before over-current protection limits power. Increase when overclocking the processor past 4.5GHz.


DRAM-AB/CD Current Capability: Increases the power threshold before over-current protection limits power. Increase to 130% if using 64GB of memory past DDR3-1866, or when running 8GB modules over DDR3-2133.


DRAM-AB/CD Voltage Frequency: Sets the switching frequency of the power FETs supplying DRAM Voltage. Lower switching frequencies lead to a higher VRM efficiency (small power saving) and lower VRM operating temperatures. Setting a higher switching frequency aids transient response (the recovery of voltage to the applied level after a load condition) – at the expense of heat. Experimentation at various switching frequencies (higher and lower) at higher DDR3 speeds may be beneficial towards aiding stability.


DRAM-AB/CD Power Phase Control: Can safely be left at Auto for most loading conditions. For overclocking 64GB of memory, a setting of Extreme is recommended.


PCH 1.1v Switching Freq: Can be left on Auto for most overclocking. If running higher BCLKs, you may wish to alter switching frequency and see if it impacts stability.




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CPU Performance Settings: This sub-menu contains SpeedStep, non Turbo multiplier ratios and CPU power settings. All settings can be left at Auto for most overclocking.

GPU.DIMM Post: opens a sub-page which shows how many GPUs are inserted into the PCIe slots and how many DIMMs are being used. If there are any peripheral issues or system bus speeds have been increased too far, one of the GPUs or memory modules may not show in the GPU DIMM Post screen – a quick glance here can save a lot of head-scratching.

A new feature for the RIVE is PCIe Lane Simulator. A sub-menu allows you to select occupied slots and then shows lane allocation accordingly in case you want to ensure optimal lane bandwidth to your peripherals.

Extreme OV: Leave at disabled unless you need to use over 1.60Vcore for benchmarking.

CPU Voltage: Two options here. The first is “Manual Mode”, which allows us to set a ‘static’ level of voltage for the CPU. The second mode is “Offset Mode”, for which we have covered the usage of here.

BCLK Skew: The sweet spot for BCLK Skew on this CPU is -2 bundled with -20 on PCIE CLK Skew. A good match in these 2 skews can help with BCLK/DRAM/Overall OC stability and help reduce Vcore requirements at a given operating frequency.

VTT CPU Voltage & 2 VTTCPU Voltage: To let users over-volt part of the CPU VTT that affects OC without over-volting the part of VTT that does not affect OC, we split up VTT rails to VTT and Secondary VTT.

VTT over-volting helps with DRAM and BCLK Overclocking. Secondary VTT does not. However, try to maintain at most a 300mv delta between both voltages for stability. 1.40v is fine on these CPUs. 1.35v is sufficient most of the time.




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CPU VCCSA Voltage: Two options here. The first is “Manual Mode”, which allows us to set a ‘static’ level of voltage for the System Agent. The second mode is “Offset Mode”, which works on the same principals as Vcore Offset Mode. VCCSA has a direct impact on memory stability, so will need increasing if you are running high density modules and/or overclocking the memory controller. As a general rule VCCSA should not be set higher than CPU Vcore as this will impact system stability. The reason for this is likely due to processor Vcore being used as either a pull-up rail for IO signaling stages, or internal DC coupling.

If overclocking past DDR3-2000, then finding the optimal delta between CPU vcore and VCCSA becomes critical with some memory modules. Hence, we recommend making small changes and monitoring for impact upon stability. It is probably wise not to exceed a voltage delta larger than 0.6V between VDIMM and VCCSA, so if VDIMM is set to 1.65V, then set VCCSA at around 1.05V minimum as a starting point AND also try to keep VCCSA within 0.3V of Vcore if possible.

DRAM Voltage (CHA, CHB & CHC, CHD): Sets DRAM voltage for the memory. Set according to memory vendor specifications or alter to facilitate over/underclocking.

CPU PLL Voltage: For most overclocking, the minimum voltage requirements will be centered around 1.80V. If using higher processor multiplier ratios or DRAM frequencies over DDR3 2200, then a small over-voltage here can aid stability.

PCH 1.1V Voltage: Can be left at stock for most overclocking. If running very high VCCSA and VTT, then over-volting this rail to maintain the same voltage delta may be beneficial.

VTTDDR Voltage: Leave at Auto unless experiencing instability with memory. As a starting point, set to 50% of DRAM voltage. So if DRAM voltage is 1.65V, then set ~ 0.825V here.


CPU & PCIe Spread Spectrum: Disable if overclocking as clock modulation can cause instability.

For Tweakers Paradise menus, we have added text into UEFI describing when to adjust parameters.



Big thanks to GSkill for providing us with the 16GB DDR3-2133 Ripjaws Z memory kit, F3-17000CL9Q-16GBZHD to help compile this guide!