Processor Voltage Regulator Circuitry and DES

We put the discussion of the GA-X48T-DQ6 processor voltage regulator circuitry into a separate section on purpose. The thing is that even though it seems at first glance that this mainboard uses a traditional six-phase processor voltage regulator, typical of top Gigabyte mainboards, it is in fact completely different from the predecessors. This board’s processor voltage regulator circuitry, just like the one on a few other new solutions from the same manufacturer, supports DES (Dynamic Energy Saver) technology that should additionally reduce the processor power consumption with a few skillful tricks.

The schematics of the GA-X48T-DQ6 voltage regulator are pretty standard. It is based on Intersil ISL6327 micro-chip that Gigabyte has been using in its mainboards for a long time already. Six-phase regulator is built with high-frequency power MOSFET, which ensures not only longer life but also higher efficiency and lower operational temperature. Besides, they use highly reliable high-quality Japanese capacitors with polymer electrolyte for the voltage regulator as well as on the rest of the board. It is pretty funny that Gigabyte’s marking people are still trying to present the voltage regulator as a 12-phase one referring to twice as many inductance coils. But, don’t buy into it.

The main distinguishing feature of this voltage regulator is its ability to switch the number of active phases during work thanks to the ISL6327 functions. This is how Gigabyte is going to ensure that their mainboard will be more economical from the power consumption standpoint. The thing is that it makes sense to use more phases for a processor voltage regulator only if the power consumption is high: in this case six-phase circuitry will be more efficient and reliable and will generate higher quality signal. It is not economical to use a lot of phases under low workload as they may eat up more power. These are the reasons that drove Gigabyte engineers to design a circuitry with variable number of active phases: from 2 to 6.

The same concept is also implemented on ASUS mainboards, however they allow switching only between 4 to 8 phases. Gigabyte promises higher efficiency thanks to five different circuitry statuses. However, this is not the only difference between ASUS and Gigabyte approaches. While ASUS offers a fully hardware solution that doesn’t require any special software, Gigabyte’s circuitry works only when you launch Dynamic Energy Saver Utility. This utility monitors processor power consumption and uses this data to adjust the number of active phases in the processor voltage regulator in real time. If it is not launched, the regulator will work according to traditional six-phase algorithm.

The information window of the Dynamic Energy Saver Utility provides the user with data on the current processor power consumption, number of active phases and the actual energy savings statistics. I would like to add that you can also see how many phases of the CPU voltage regulator are active from the row of multi-color LEDs on the mainboard PCB located to the right from DIMM slots.

Besides the phase switching within processor voltage regulator circuitry, Dynamic Energy Saver Utility also does a few other things aimed at saving even more power. Firstly, this utility reduces the processor Vcore by 0.05-0.08V. There is a CPU Voltage Level switch that determines how greatly the Vcore will be lowered; however, unfortunately, you cannot skip it completely. Secondly, this utility can also enable processor throttling if you want to, so that the CPU will skip every other clock cycle under low workload.

As a result, we can conclude that DES technology first of all saves power in idle mode. In case of full CPU utilization, throttling will be disabled and the voltage regulator will activate all six channels. The only way to save power in this case is the forced lowering of the processor core voltage, which is more of a trick than an engineering approach.

To prove everything we have just said, we measured the power consumption of a quad-core Core 2 Extreme QX9770 processor in case of different DES settings. Enhanced Intel SpeedStep was activated.

As we see, DES technology does reduce the processor power consumption and power losses in the voltage regulator circuitry. The obtained results prove this statement with all certainty. But do not forget that the mainboard drops the CPU Vcore below the nominal value, which may lead to potential loss of system stability and overall, can hardly be considered a technologically fair approach. The same thing can actually be done on any mainboard that allows manual adjustment of the processor Vcore parameter. Unfortunately, it is impossible to estimate how efficient changing the number of active phases in the processor voltage regulator circuitry in real time actually is, because once DES is launched, the processor Vcore inevitably drops.

So, the current DES version is pretty interesting from the theoretical prospective, but its practical implementation still arouses a number of serious questions. Firstly, the processor Vcore drops below the nominal regardless of the user’s wishes. Secondly, DES requires installation and non-stop operation of a special utility. And thirdly, this technology doesn’t work with overclocked processors.

In other words, DES will hardly be of interest to computer enthusiasts at this time. at least until Gigabyte engineers make a few changes to it.