Voltage Regulator Module or VRM is one of such components that we do not talk or hear about much. But we have to realize that a stable computer is only possible in the presence of a quality VRM. From providing the required voltage to different parts on the motherboard to supplying clean power, a VRM performs an integral function in our computer. In this guide, we are going to talk about VRM, its constituents, how it functions and why it is important for having in our system.
What is a Motherboard VRM?
The components on your motherboard do not need all the 12 V power supplied by the power supply unit. Most of the circuitry is so delicate that it requires very less voltage to function. Hence, a motherboard needs a mechanism to supply these minute amounts of power. VRM, as the name suggests, is a component that regulates the voltage coming from the PSU and transfers the required voltage to the CPU after cleaning it of spikes and surges. It also supplies the designated voltage to RAM or other parts. You can find the VRM embedded on the motherboard near the CPU. Just like a PSU converts high voltage from the power socket of your home into the amount necessary for your system, a VRM takes high voltage from the PSU and steps it down. Hence, You can consider it as a mini power supply unit. The VRM is not a single chip or a wire on the motherboard. It supplies the clean and regulated energy through the integration of operations performed by its constituent parts. Let’s see what it is made of.
What Constitutes a VRM?
A single-phase Voltage Regulator Module is made up of three main components; two MOSFETs, a Choke and a Capacitor. Most of the motherboard has multi-phase VRM and consists of multiple numbers of these components. You can find the MOSFET under the heat sinks as they tend to generate a lot of heat. You will see large coils, that is, the Choke around the CPU near the MOSFET. Similarly, the capacitors are placed on the side of the Choke which are mostly in a cylindrical shape. The MOSFET sends the required voltage to the CPU through the instructions from Pulse-Width Modulation (PWM) controller or driver IC. Its full form is Metal-Oxide-Semiconductor Field Effect-Transistor and is responsible for the transfer of regulated voltage. The Choke is nothing but a magnetic inductor that generates a voltage by self-induction in it to oppose the power obtained from the PSU. The MOSFET cuts the induced voltage when it reaches a fixed value and supplies it to the CPU. The Capacitor receives the ripple voltage with spikes and sudden surges and converts it into cleaner and stable voltage. Its job is to prevent damage by controlling the ripples in voltage.
How Does a VRM Function?
The VRM consists of an electronic circuit made up of connections between the MOSFET, Choke and Capacitor. In a simple language, the MOSFET receives the high voltage from the PSU and charges the inductor till the required voltage. The voltage from the Choke output is then passed to the CPU with capacitor storing and providing energy to make it ripple-free. Let’s look at the process in detail now. When your PSU supplies voltage to an inductor or a Choke, in this case, through the MOSFET, it resists the flow of current and instead creates a magnetic field around it. Due to this, the voltage on the output side of the Choke increases slowly while the resisted voltage generates magnetic energy. This is known as charging. If we leave the power to flow for a longer time, the inductor fully charges and its output will have the same voltage as the input. So, when the Choke discharges from the MOSFET switch and a diode on the Low Side, all the voltage will pass to the CPU. But, the CPU only requires a portion of the input voltage, roughly around 1.2 V from the 12 Volts of PSU. Hence, the circuit needs to have a feature to remove the input power when the output voltage reaches 1.2 Volts. So, the MOSFET takes instruction from the PWM controller which monitors the width of the pulse. It causes the Choke to discharge right when the required voltage is reached at the output. The manufacturers have designed the circuit such that when the High side switch opens, the Low side closes and discharging begins and vice versa. This creates a controlled amount of output voltage to pass from the Choke to the CPU or the load with continuous charging and discharging of the Choke. But, the CPU takes the large portion of energy from the Choke that causes the Choke to take time to receive charging voltage for the next round. So, to compensate for this and reduce the ripple, the circuit consists of a capacitor. The capacitor stores some energy from the earlier round and supplies the required energy for the next round to charge the Choke. Finally, the circuit completes and the CPU receives stable energy continuously by the repeated process. To provide more stable power, a number of such circuits are connected. This is called a multiphase VRM. Here, the PWM powers each VRM turn-by-turn reducing the fluctuation much more. Hence, the multiphase VRM supplies more stable power. Now that we know how a VRM operates, let’s learn about why it is so important to have a VRM in a motherboard.
Why Is It Important?
As we have mentioned earlier, the CPU does not require all the power coming from the power supply unit. If we were to supply the full voltage to it, the CPU would get fried instantaneously. Here, the VRM plays the role of the voltage regulator and supplies exactly the voltage required by the CPU. The VRM regulates power for other hardware such as RAM as well. We can find the specification as “4 + 1” or “8 +2”, meaning 4 or 8 phases of VRM are for CPU and 1 or 2 for RAM or HyperTransport. Aside from this, there are several other importance of the VRM. Let’s go through them together.
Clean and Stable Power to Hardware
The hardware within the motherboard such as the CPU, RAM, GPU are very sensitive to power fluctuation. Even the slightest variation in voltage can permanently damage the system. The VRM not only provides the ripple-free and stable voltage to the CPU but also serves the same for RAM and sometimes the GPU as well. Most of the motherboard consists of multiphase VRM, meaning the voltage is cleaned for more cycles making the system even safer and more stable. Hence, the more are the phases, the more is the stability of the system.
Helps in Overclocking
We can see the direct impact or advantage of VRM during Overclocking. Overclocking of the CPU means running the processor at a speed higher than designated. This process requires more power to be input into the CPU. Most important thing is that the power needs to be stable. A Multiphase VRM divides power obtained from PSU to every phase with each phase consisting of a small portion. The output voltages from each phase enters the CPU turn-by-turn preventing the higher fluctuation. It makes the voltage much more stable as we have mentioned earlier. Similarly, more VRM phases mean that more power can be pumped to the CPU, and that too in a steady form. Hence, you can use more power during overclocking safely and without causing any fluctuation in performance.
Prevent Damage of Components and BSOD Errors
All the components are connected to each other through some circuitry in the motherboard. An unstable CPU can not only fry itself but also damage other components in the board. If the power supply to the CPU or RAM exceeds the optimum value, it can cause serious hazards to the system. Similarly, an unsteady power supply is a root cause of several hardware and software issues. It causes the system to show BSOD errors and will make working on the system troublesome. The system also shuts down frequently if the power supply requirement is not met. The presence of VRM on the motherboard helps to prevent all these problems. A good VRM will prevent fluctuation in power, thus helping the processor and other hardware to function without any disturbance. In addition, since the VRM is so important, it is better to look at the specification for VRM while buying a motherboard. You can also easily count the number of phases by counting the number of Chokes on it. Furthermore, It is essential that the VRM is kept cool properly. During heavy load, it is normal for the MOSFET and the VRM as a whole to heat up. The manufacturer normally provides heat sinks and thermal paste for passive cooling of the VRM by using heat sinks and thermal pastes. Besides that, we would advise you to keep your system cool all the time to prevent from overheating VRM.
