Last Updated on November 6, 2020
Regardless of how and where you get it from, power is vital for any electronic device to function and a computer is no exception. Well, I’m sure you already know this much. However, there are certain aspects of power supply that most people are unfamiliar with.
The computer is made up of many different components that have different power needs. All these pieces are connected to the same power supply there needs to be a way to ensure that no component gets more or less power than it needs.
Failure to regulate power properly on your computer can lead to system instabilities and at worst can fry your system.
Before delving into the topic about what is VRM on motherboard, it is worth talking about the PC power supply first.
Also Read: What is Motherboard Form Factor?
Power supply unit is the primary component that step the wall voltage of 110/220 volts to 12 volts.
You will need a good power supply that can effectively step down the voltage of the power you get from your wall outlet to a value that is safe to use on your computer.
Power Supply Unit or PSU is one of the most important things to consider when buying parts for a PC because the quality of your power supply as well as it rated power will determine a lot when it comes to customizing your builds.
A cheap one can result in unstable power which is undesirable, so always aim to buy a good quality unit from a reputable manufacturer if you value efficiency.
Power supply units are rated at different power outputs and you will be required to get one that at least matches the use case you intend for your system if not more.
For instance if your components all together have a rating of 500 watts, you should at least aim for a 600 watts Power Supply Unit.
High output power supplies are usually more expensive. Along with the rated power, the efficiency is also a core determinant but that is topic for an other article.
Also Read: Will Motherboard POST without CPU?
Supported Power and VRM
Most motherboards are rated at 1.1v – 1.3v. The range depends on many factors one of which is overclocking. When overclocking, the motherboard takes a higher voltage.
The Power Supply Unit gets 110v or 220v from the wall and it then steps it down to 12V.
So how do you step this voltage further down to the rated 1.1v-1.3v? Well that is where motherboard VRM come into play.
You may be wondering why doesn’t the PSU just step down the wall voltage all the way down to 1.1v – 1.3v? Well, that is because the peripheral components i.e the hard disk and the graphics card require 12v to operate.
Why can’t motherboards operate at a higher voltage? Basically, because the very tiny semiconductor would literally melt their silicon if given a higher voltage.
What is VRM on Motherboard?
Now that we are familiar with what a power supply unit is, it’s time to get into the woods. A VRM or Voltage Regulator Module is a component that works between your computer’s PSU and motherboard, CPU as well as the RAM.
It has the singular purpose of ensuring that the 12 or so volts from the power supply output is further stepped down to the 1.2 – 1.3 volts that are needed by the CPU depending on whether or not you’re overclocking it.
If you’re wondering why this is important, a VRM ensures that the CPU gets the voltage it requires, nothing more and nothing less.
It also keeps the power levels within acceptable values. That is, it ensures that sudden power spikes and dips do not reach the critical components.
With High voltages, you can burn the CPU and low voltages from a poorly made VRM can cause system instabilities and crashes.
Unlike many other components of a motherboard, the VRM receives very little attention despite the critical role that it plays on a motherboard.
Where is the VRM Located?
A lot of the time the VRM is located somewhere near the CPU. It can be easily spotted by the chokes and capacitors that it has accompanying it.
We will get to these a little later. It may also have a heat sink that’s used to dissipate the excess heat that is generated when stepping down the voltage to a lower value.
How the VRM works
The VRM’s function is to stabilize the voltage that is received from the power supply, smoothen it and get it to a level that can be used by the CPU and the memory with little to no effect, essentially, to ensure that these components receive stable power.
To do this, it makes use of three main components, the MOSFET, Inductors, and Capacitor.
1. The MOSFET
This is short for Metal-Oxide Semiconductor Field Effect Transistor. It is further made of three parts, a gate, a drain, and a source.
The GATE controls the MOSFET and the SOURCE is connected to the, well, source of power or current (PSU). The DRAIN is where the current from the SOURCE flows to when the MOSFET is activated from the GATE.
This component works like a switch, capable of turning on and off when a voltage is supplied or turned off at the GATE.
When the GATE receives voltage, it allows the current from SOURCE to pass to the DRAIN.
The MOSFET in the VRM is directly controlled by the CPU as it literally receives instruction to deliver a certain level of power.
The better the MOSFET, the better control it would have.
2. The Inductor
This component can be easily spotted on a motherboard as it commonly looks like a metal cube. You may have heard it being referred to by a more common name, the choke.
It serves two functions. It can store or filter energy depending on what is required. Unlike a capacitor that stores charges, this device stores energy in a magnetic field and it does a lot to control the overall current that the VRM can emit in each phase.
When overclocking, chokes improve the device’s ability to step down voltage and improve its overall efficiency with handling power.
3. The Capacitors
This is a common electrical component used in any electronics to store energy in an electric field and when required, can discharge this energy into the circuit they’re connected to.
There are many types of capacitors available and a good one will serve you for a long time. Poorly manufactured electrolytic capacitors have liquid inside that may leak out and cause damage in your system.
A good VRM will most certainly make use of high standard and high quality capacitors. These include capacitors branded as Solid Capacitors, Hi-C Capacitors etc.
Capacitor vs Inductors 101
Capacitors store voltage by storing energy in an electric field. Inductors store current by storing energy in a magnetic field.
All these components are grouped in a specific way to form a VRM phase that is responsible for regulating power.
You can always deduce the number of VRM phases you have on your motherboard by counting the number of chokes around the CPU.
Each choke will be part of a phase and in multiphase motherboards, we get better power stability.
This is because in multiphase VRMs, power is checked multiple times before being directed to the components.
Each VRM phase checks whether the voltage is being delivered at the right amount. If it is not, it then steps it the right voltage.
The higher the VRM phases, the cleaner and smoother would be the power supplied to the motherboard be.
How to Know How Many VRM Phases your Motherboard Has
Some motherboard specifications will tell you exactly the phase design in the form of following numbers:
The number preceding the + sign is the amount of VRM phases for the CPU. The number after the + sign is the number of VRM phases for the RAM.
Higher end motherboard have higher number of VRM phases for CPU and RAM.
If a motherboard spec sheet does not specify the phase design, then you can figure out the amount of VRM phases by counting the chokes generally located around the processor socket and the RAM.
Here we talked specifically about what is VRM on motherboard. Basically, a VRM can be considered a mini power supply. Just like a full-size power supply unit, the VRM takes a voltage and steps it down to a manageable level that can be utilized by components on a motherboard.
It also ensures that the voltage level is smooth to avoid sudden power surges that can cause problems for a computer.
This tiny component is so important and needs a lot of attention because it can effectively dictate the performance of a computer.
Not all VRMs are created equally though. Higher end MOBOs feature higher VRM phases as well as better VRM component quality.