How to tweak DIGI+ VRM on P8P67 Series motherboards

The latest evolution of CPU power hardware – DIGI+ VRM – is now used on all ASUS P8P67 Series motherboards. Combined with the all new UEFI BIOS replacement and all these new options in a new interface could seem a little overwhelming. Where do you start? What do each of the new features do and what’s the best settings to tweak when overclocking?

First things first though: update that BIOS.

Grab the latest version for your motherboard at the ASUS website (Products – PC Components – Motherboards – Intel socket 1155 – select your chipset and motherboard – then go to the download tab).

Put the new UEFI BIOS file on a FAT32 formatted USB stick and plug it into your new PC. Boot your PC and go into its UEFI BIOS, click into advanced mode in the upper right corner, then select the Tools tab. Select the ‘ASUS EZ Flash Utility’, select the file from your USB flash drive and update it. Job done!

One you’ve updated everything, go back into the advanced mode again. You can set it to always go here first under the Boot tab.

Now lets get into the nitty gritty:

Firstly: How do I overclock?

Under the AI Tweaker tab, you’ll find a range of overclocking tools. If you’re still unsure about overclocking the CPU, then the OC Tuner setting is equivalent to the Turbo Key II switch on the motherboard: both will take over and automatically overclock the CPU without any further input from you. This usually provides a great start and notable performance bump, but the downside is that it’ll likely not push it as far as manually tweaking it.

To overclock your CPU manually increase the number in the Turbo Ratio. This is multiples of the BLCK/PEG Frequency above (usually 100), which means setting it at 45 (for example) = 4,500MHz or a 4.5GHz CPU. A very large, but usually attainable overclock for either the i5-2500K or i7-2600K processors.

If you’re concerned with power use then play around with the EPU setting. This generation of EPU is tied in directly to the DIGI+ VRM chip so it can actually work with the power hardware rather than forcing you to make a choice between power saving and overclocking. For extremely heavy overclocks or if you prefer to manage things manually (see below), most people still prefer to turn it off.

ASUS P8P67 UEFI AI Tweaker - CPU Overclocking area

DIGI+ VRM settings explained:

Don’t be afraid to use the ‘Auto’ option. Instead of meaning ‘only standard voltage’, this time around ‘Auto’ will actively compensate any increase in clock speed set by you. If, again, you’re unsure of things and don’t want to blast too much voltage through your expensive new processor, then this method should work fine. You still need to pay attention to your temperatures though – they are in the Monitor tab. Because each CPU is manufactured with slightly different tolerances, try using the Auto voltage as a reference, then manually lower it until you lose overclock stability. This will lower temperatures and save you power.

Adjusting the Load-Line Calibration setting higher means it’s less likely the CPU core voltage will ever suffer a drop (known as vDrop and vDroop) as it does work. The downside is an increased likelihood of a bit of voltage overshoot and greater temperatures, however it’s very unlikely to be fatal to a CPU unless you manually set very high voltages to begin with. For most people this can be left to Auto, however ‘High’ is sufficient for air-cooled overclocks.

ASUS P8P67 UEFI AI Tweaker - DIGI+ VRM Area

The VRM Frequency setting refers to the DIGI+ VRMs specifically and can also be left to Auto for air-cooled overclocking.  As the VRM frequency is increased it become more responsive to changes in CPU load, so a higher setting will benefit overclocking. However, as with increasing the frequency of anything, this also generates more heat so be mindful that those blue heatsinks will need adequate airflow. Thankfully the T-Probe will moderate the temperature by dynamically distributing the load between them all, thus keeping a uniform temperature. You can try anything up to the maximum value of 500Hz safely, as ASUS says this is still within the acceptable specification.

To complement the speed at which the DIGI+ VRM works, the Phase Control function works to vary the amount of DIGI+ VRM power phases are in use at any one time. Reducing the number active when the CPU is idle can save power and component life-span. The ‘Standard’ Phase Control setting follows the Intel specification directly on something called the CPU PSI (Power Status Indicator) signal. ‘ASUS Optimized’ is a setting more finely tuned by ASUS engineers to the efficiency of the DIGI+ VRM, which again can save additional power while retaining full stability. If you still want full control over the rate at which the power phases are changed rather than leaving it to just Intel or ASUS, there is a setting that offers a set of custom control. ‘Medium/Faster/Ultra Fast’ represent how quickly the system should respond to the CPUs power demands, changing the number of active power phases. Obviously faster is better for overclocking, and ASUS says even the Ultra Fast and Extreme settings are OK to use. Try this out if you are concerned with power saving, but still want to overclock heavily.

ASUS P8P67 UEFI AI Tweaker - CPU voltage area

The Extreme setting disables this function making all the phases fire up all the time. At standard CPU speed and with light-medium overclocks, the ASUS Optimized option is best, especially if you’re using the EPU technology to try to save power, however overclocking and overvolting meaning only will benefit from using the Extreme setting to take full advantage of the 12-16 DIGI+ VRM power phases.

Where the Phase Control option above controlled how many DIGI+ VRM phases are be loaded, the Duty Cycle represents how much each of the DIGI+ VRM phases will be loaded by. Combined together, it’s important to try and strike the best balance between the two. With the T.Probe function, the motherboard can dynamically change the power weighting to each phase according to the temperate of each DIGI+VRM MOSFET in order to prevent hotspots and reduce the overall heat output. This is ideal for low airflow and water-cooled systems, where hotspots around the CPU socket are more likely. In the Extreme setting, the DIGI+ VRM ignores the temperature and balances the power evenly over all phases in use, all of the time.

Finally, the CPU Current Capability is the total power current available to the CPU cores. Intel purposely limits it within the CPU, however it can be overridden with this UEFI option. Limiting the power available to the CPU this also limits the overclocking too, so increasing this percentage can increase the stability and range of overclocking. The most recent BIOS updates have allowed ‘Internal PLL Overvoltage’ within the CPU as well, but this only concerns overclocking to the limits, rather than light-average overclocks. Still it’s just another reason why we recommended updating the BIOS at the start!

If you have any questions or comments about the new DIGI+ VRM system, tweaking, overclocking or your own advise about what works best on your P8P67 Series board, drop us a comment below!

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