Because of the ease we have when building a PC, we often do not appreciate the electrical engineering that is carried out to make everything work. For example, how does the motherboard manage the way the processor gets the power it needs to function? It does this through voltage regulator modules or VRM for its acronym in English, and in this article we are going to tell you what exactly a VRM is , how it works and how it affects the performance of the processor .
When we talk about PC motherboards, it is often mentioned that they have X-phase VRMs where we all appreciate the fact that the one with a higher number of phases is better, especially if you intend to overclock the processor . This basis is essentially true, but to reach this conclusion we are going to delve a little deeper into the matter to see how this whole system of power delivery to the processor works.
What is a VRM and how does it work?
The VRMs on your motherboard consist of a number of crucial but underrated electronic components, since they are what ensure that the processor or even the graphics card receives a clean power supply and, most importantly, with the exact and constant voltage that need.
A poor VRM system can cause degraded performance and limit the processor’s ability to operate under high load; it can even lead to unexpected blackouts, especially when overclocking.
The first job of a VRM is to convert the 12V power coming from the power supply to a voltage value usable by the PC components. In the case of processors, this voltage usually ranges between 1.1 and 1.3V, and is that the delicate components inside can easily short-circuit when the proper voltage is not supplied. Accuracy is also crucial when powering a CPU, and the required voltage must be supplied as accurately as possible. For this reason, VRMs are much more complex than a simple cable, although basically their operation is essentially based on behaving like a step-down converter , converting the voltage precisely to the appropriate levels.
The VRM uses three components to do its job: MOSFETs, inductors (also called chokes), and capacitors. There is also an integrated circuit (IC) to control everything, sometimes called a PWM controller; Below you can see a simplified diagram of how a single phase VRM works.
Multi-phase VRM (processor + RAM)
Modern computers require more than one single-phase VRM, which is why modern motherboard power systems use multi-phase VRMs or multiphase VRMs. The multiple phases distribute the power load over a wider physical area, thus reducing heat production and stress on components, as well as providing other electrical improvements related to efficiency and cost per part.
Each of the phases of these modern VRMs supplies a fraction of the required power, taking turns providing full power to the processor. Taken individually, each phase provides only a brief moment of power, visualized as a square-shaped wave.
The energy burst for each of the phases is staggered from the last one, so while only one phase works at a time, the total amount of energy never changes. This, in turn, produces a smooth and reliable power source, just what a processor requires to function optimally. You can see a simplified system of operation below.
The truth behind the phase announcements
Motherboard manufacturers typically advertise their product VRMs as the sum of two figures, such as “8 + 3” or “6 + 2”. The first of these numbers indicates the number of phases dedicated to cleaning power for the CPU, while the second figure indicates the phases of VRM that remain to power other components of the motherboard, such as RAM memory.
When the first number is greater than 8, such as 12 + 1, 18 + 1, or even more, the manufacturer often uses a device called a duplicator. A duplicator allows them to multiply the benefit of existing phases without having to physically build additional phases on the motherboard PCB. Although this is not as effective as the completely separate phases, it does allow some electrical improvements in the whole and obviously its manufacturing cost is much lower.
Of course, since this technique allows manufacturers to increase the number to the buyer at a small cost to them, they often take advantage of marketing strategies to “sell” their plate as if it were better than it is. Be careful with that.
How do VRMs affect processor performance?
The objective of the VRM circuit is the provision of clean, reliable and efficient energy. However, even a basic VRM can offer enough performance to keep a mid-range CPU at standard speeds, but it is precisely when overclocking or pushing the limits of components that the quality of VRMs becomes more important.
Overclockers should look for motherboards that have reliable component VRMs. If the components are cheap and of poor quality, it is likely that they will not provide enough voltage under load, which will cause system hangs especially when overclocking. The components that most affect this are the capacitors that you can see marked in green in the image above.
Therefore, if you are looking to overclock you should look for boards with good quality capacitors, often marketed as “Japanese 105C capacitors”, “solid state capacitors” or “dark capacitors”. Very high overclocking levels also require the chokes to be of good quality, and in this respect they are often called SFC (Super Ferrite Chokes) or “Premium Alloy Chokes”. You should also make sure that the MOSFETs have their own heatsinks, since this is the component that generates the most heat.
Also, those who use higher-powered CPUs like AMD ThreadRipper should make sure that their motherboard VRMs are of good quality even if they are not going to overclock. Many manufacturers are prepared for the consumption of ThreadRipper processors, but when the CPU consumes a lot of power the quality of the VRMs can make the difference between having good or bad overall performance.
In any case, even with knowledge it can be difficult to know if a motherboard has good VRMs for the processor you intend to mount, especially since many board manufacturers use the VRM phases as mere marketing material.