All modern motherboards come with something called a voltage regulator module (VRM). The intent behind adding this to the motherboard is to convert an incoming alternating current (AC) into direct current (DC), which powers most of the components on your motherboard.

VRMs are frequently found in modern CPUs and GPUs. They’re used to control the voltage sent from your system’s motherboard, which is important because it can lead to hardware failure if not regulated properly.

For example, if you are using one of AMD’s Phenom II CPUs that runs at 95W, that’s a heck of a lot of power. So naturally, the motherboard requires a very stable and robust voltage source to provide a continuous, smooth current. Unfortunately, the PC power supply usually can’t do this job by itself, so you need to have an additional circuit on your motherboard called the VRM to convert incoming AC into DC.

What does the VRM do?

VRM Diagram

All that is required for a voltage regulator module to function is three simple elements: input, conversion, and output. The input is usually what you’ll find on your power supply (AC), while the output is where all your components will get their DC (the motherboard). Finally, there’s the conversion between these two; this part of the circuit converts incoming AC power into DC for powering your components.

To do this, the VRM circuit will use one or more MOSFETs (metal-oxide-semiconductor field-effect transistors) to regulate voltage. It’s an electronic component that acts like a switch but is controlled by current instead of voltage, somewhat similar to a relay. It’s very simple in its design, but when these MOSFETs are put together and hooked up to each other, they become a powerful and efficient voltage regulator for your motherboard.


the pwm

At the heart of every VRM is something called a PWM (pulse width modulation) controller chip. It is basically an integrated circuit (IC) that acts like the CEO of the VRM. It manages everything, making sure each component is doing its job properly. For example, it will monitor voltage output, temperature, and current draw to ensure all aspects are within optimal levels.

The MOSFETs used in a VRM are rated by wattage; it is the maximum amount of wattage they can dissipate. If this number is exceeded, your MOSFETs will be fried, and you’ll have to buy new ones. It means that your motherboard may work with 65W CPUs just fine, but when you upgrade to an overclocked 95W Phenom II CPU that runs five degrees hotter than the 65W CPUs, it may be the end of your motherboard.

The Importance of VRM

VRM is a much-needed and essential component as it is vital to know just how much wattage your components require and what the maximum amount of wattage your power supply can output. If you’re not sure about any of this, just check out a few reviews on sites such as Newegg or Tom’s hardware, and you should be good to go.

There is no need for a VRM if your PC’s power supply can provide enough wattage and voltage on its own so that this circuit will work even without one. However, a VRM offers more stability and efficiency than just using the regular power supply by itself. It also allows you to overclock your motherboard without worrying about whether it’s going to explode.

The voltage regulator module on a motherboard does its job quite well, but it needs to be cooled in order not to overheat and cause damage. As such, VRMs found on motherboards usually have a small heat sink and fan combo dedicated just for this circuit.

Of course, the majority of PC power supplies come with active cooling out of the box, so you don’t have to worry too much about it. However, if you decide to buy a new PSU for your system and it doesn’t have one, you can always pick up any extra fan that will fit on the back of your motherboard. That should do the trick just fine.

Bottom Line

To quickly recap:

  • The power supply provides AC.
  • The voltage regulator module (VRM) converts AC to DC.
  • Your motherboard’s MOSFETs regulate voltage and provide a continuous, smooth current for all your components.

For more information on what a VRM is and how it works, you can check out our video on this topic below.

I hope you have found the information presented in this post interesting and informative; please leave your feedback in the comment section below. Also, feel free to ask any questions you might have.

Yasir Jamal
Hi Folks, meet Yasir Jamal here. As a blogger for more than five years, I have written more than a million words, and my motive is to help people get the correct information. As a review blogger, I offer unbiased reviews of products and also share helpful tips on DIY projects. So please stick with me and learn something new every day!