How to Undervolt a CPU: Step-by-Step Guide

To undervolt a CPU, lower the voltage it requests in small steps, using Curve Optimizer on supported AMD Ryzen chips or a voltage offset on supported Intel chips, then stress test after every change and back off one step from the first instability. Done conservatively, it can reduce heat and power draw with little or no loss in performance, but it is a tuning change that can cause crashes and may affect warranty terms.

What Undervolting Does

Every CPU requests a voltage for each clock speed from a built-in voltage and frequency curve. The factory curve includes generous safety margin so that even weaker chips from the same batch stay stable. Undervolting trims that margin. Lower voltage means less heat and lower power at the same clocks, which can let a CPU boost higher or longer before it hits a thermal limit, and can make fans quieter. Gains vary by chip, and results from reviewers range from a few degrees to larger drops.

Prerequisites

• A CPU and motherboard that expose the controls. Locked processors, many pre-built PCs and laptops, and some entry-level chipsets hide them. On AMD, Curve Optimizer options may be missing or greyed out on some chipsets such as A620 or if Precision Boost Overdrive is off. On Intel, undervolting is usually best supported on unlocked K-series chips, and some boards or BIOS versions apply undervolt protections.
• The latest stable BIOS from your motherboard maker.
• Monitoring software such as HWiNFO64 to log temperature, power, and clocks.
• A benchmark and a stability test, for example Cinebench for scoring, plus a stress tool such as Prime95, OCCT, or CoreCycler for Ryzen.
• Your motherboard manual, since menu names differ between makers.

A Warning Before You Begin

BIOS changes can cause instability, data corruption from crashes, or a PC that will not boot until the CMOS is cleared. Undervolting and overclocking can void warranties depending on the maker, so read the terms. Keep changes small, make one at a time, and write down your original settings. Too little voltage rarely damages hardware, but it can crash games and corrupt open files, so save your work first.

Step 1: Record a Baseline

1. Restart the PC at stock settings with nothing else running.
2. Run a benchmark and note the score.
3. Use HWiNFO64 to log CPU temperature, package power, and clock speeds during the run.
4. Save these figures to compare later.

Step 2A: Undervolt a Ryzen CPU With Curve Optimizer

1. Enter the BIOS (commonly Delete or F2) and look for advanced or tweaker menus. Curve Optimizer usually lives under AMD Overclocking, Precision Boost Overdrive, or a similarly named page.
2. Set Precision Boost Overdrive to Advanced instead of Auto if needed.
3. Open Curve Optimizer and choose All Cores.
4. Set the sign to Negative.
5. Enter a small magnitude. Guides vary: some suggest starting around 10, others 15 to 20. Starting lower is safer. Each unit is a small step on the voltage curve and is not a direct millivolt value.
6. Save and exit, then boot into Windows.

Many guides suggest finding a stable all-core value first, often in the range of -15 to -25 on chips that tolerate it, and only then adjusting individual cores. Per-core tuning takes much more time and testing.

Step 2B: Undervolt an Intel CPU With a Voltage Offset

1. Enter the BIOS and open the CPU voltage or overclocking page. Names such as CPU Core Voltage, Adaptive Voltage, or Voltage Offset appear, depending on the board.
2. Switch the mode to Offset or Adaptive if available.
3. Enter a small negative offset. Guides for recent chips, including Core Ultra 200S, suggest starting around minus 20 to minus 25 millivolts, then moving in small steps. Your own chip may differ.
4. Save and exit.

Intel’s own tuning utility is another route on some systems, but Windows-based tools may be blocked by security settings or firmware locks.

Step 3: Stress Test

1. Run your benchmark again and compare score, temperature, and power to the baseline.
2. Run a stability test for at least 30 minutes, longer for a final setting.
3. Play a game you know well. Light-load instability, such as crashes at idle or when boost drops, can appear after heavy tests pass.
4. If everything is stable, deepen the offset by one small step and repeat.
5. When you hit a crash, restart, return to the last stable value, and then back off one more step for margin.

Quick-Reference Table

What Result to Expect

You should see lower temperatures and package power at the same workload, and similar or slightly better scores because the chip has more thermal and power headroom. Some chips undervolt well and others hardly at all, a variation sometimes called the silicon lottery. If the benchmark score drops or becomes erratic, the CPU may be correcting errors internally, which can happen before an outright crash, so go back a step.

Common Mistakes

• Jumping straight to an extreme value from a forum post. Every chip is different.
• Testing only with one stress program and skipping real games and idle behavior.
• Changing several settings at once, which makes problems hard to trace.
• Forgetting to update the BIOS before tuning, since new versions can change behavior.
• Ignoring a reduced benchmark score as if it were fine.
• Applying a profile from someone else’s chip without testing it.

When Not to Undervolt

Skip it if the PC is under warranty and the maker excludes tuning, if you rely on the machine for work where a crash costs data, if temperatures are already comfortable, or if your hardware is locked. Raising airflow or setting a sensible power limit can be a simpler first move. If the system will not boot after a change, clear the CMOS as described in the manual. If it still misbehaves, contact the motherboard or CPU maker or a technician.

Frequently Asked Questions

Will undervolting damage my CPU?

Reducing voltage within normal ranges is generally considered low risk to the hardware, as it lowers heat. The main dangers are crashes and file corruption from instability, plus possible warranty issues. Use small steps and test.

Is undervolting the same as underclocking?

No. Underclocking lowers frequency, while undervolting keeps the clocks but lowers the voltage requested. A good undervolt aims to keep performance the same or better.

How do I know if my undervolt is unstable?

Signs include crashes, blue screens, game freezes, application errors, and failed stress tests. Ryzen users sometimes see issues at idle or light load, so test across different workloads.

Can I undervolt a laptop CPU?

Many laptops lock the controls, and some manufacturers disabled them through firmware updates. If the option is not in the BIOS and the maker blocks software tools, it is not available.

How much cooler will it run?

It varies by chip and workload. Reviewers report results from small drops to double-digit degree reductions on hot-running chips, but there is no guarantee for any specific processor.